ISEE-3 in Interplanetary Space

The International Sun-Earth Explorer (ISEE-3) Reboot Project, Bringing an Old Bird Back to the Earth, and Back to Life

Life isn’t fair. So many times in my life I start to do something and end up going in a completely different direction. I do a lot of advanced technology spacecraft and systems design for lunar, mars, and asteroid exploration. I love to think about, plan, and build systems that will help mankind extend its reach beyond the Earth.   I was very fortunate that when I left the computer industry in my late 20’s to return to college and get my degree I was able to have many wonderful mentors at the University of Alabama in Huntsville. Some of these were  German rocket scientists like Dr. Ernst Stuhlinger and many of the Americans who made up the team that built mankind’s first lunar exploration system. Also, when I was in my early 20’s in the early 1980’s I worked as a non-degreed engineer in the California computer industry. I had great mentors there as well, who taught me how to be a good engineer in the extremely competitive microcomputer industry of the era.

One of the companies in the microcomputer industry back then was Vector Graphic Inc. who, before the advent of the IBM PC, was one of the leaders and innovators in the industry.  My boss and the manager of engineering was Nick Esser, an incredible engineer and a great mentor.  I would often come bounding into his office with what I thought was a great idea.  He would immediately stop me and say, sounds good, now go research what has already been done in this area.  Well we did not have the online resources that we have today so in order to impress the boss, I would go and do a lot of in depth research, perusing IEEE proceedings, textbooks, ask people questions.  I would often determine that my bright idea was someone else’s before me and often they had usually done it better.  This taught me two things.  The first is that there are a LOT of smart people out there, many of them much smarter than I (when you are 22 this is a revelation).  The second was that in doing this research I would almost always come out smarter myself.  I took this incredible lesson with me to my college years and it has made a critical difference for me in how I think about technology and engineering in general. It is also the origin of the life is not fair comment.

How the Above Relates to the ISEE-3 Project

Many of you know about our Lunar Orbiter Image Recovery Project (LOIRP), and many of you who read this helped us out last year as we raised a critical $68k dollars that helped us get over the top to obtain more funding, which has allowed us to finish the tape captures (thanks!).   That project started when I was working in 1989 with Lunar Orbiter Lunar images derived from film, and found out after my research that the original tapes had much higher dynamic range.  This gave me the technical foundation to sell the project to NASA in 2008 after we found and obtained the tapes and tape machines.  Despite deep skepticism that the project was viable or worthwhile we were able to show the improvements to worldwide acclaim and thus gained the credibility that we could work with and improve old data sets.

Like most engineers and scientists I would rather work on new missions but it just kept bugging my engineering sensibility that these tapes were not being saved and also I knew that if our team did not take on this project, no one else would, and thus an incredibly valuable part of our history as well as incredibly valuable data for future science and exploration would be lost.  Now that the LOIRP project is coming to a successful conclusion, another instance of a violation of my engineering sensibility has taken place.  That violation is that a spacecraft, originally called the International Sun-Earth Explorer or ISEE-3 is coming back to Earth in August and if something is not done it will be lost forever.  Why should anyone care?  That my friends is the rest of the story and why I am going to ask you to liberate some of your hard earned cash to give to this project…

The ISEE Mission

The ISEE-3 vehicle was the third of three spacecraft, two from NASA and one from ESA. Figure 1 is the NASA graphic for the mission:

Figure 1: ISEE-1,2, and 3, launched 1978
Figure 1: ISEE-1,2, and 3, launched 1978

The three ISEE spacecraft are comprised of a mother/daughter (ISEE-1/2) configuration and a heliocentric spacecraft (ISEE-3). The ISEE-1 and -2 spacecraft, mated together, were launched on October 22, 1977, and the ISEE-3 was launched on August 12, 1978. The purpose of the ISEE Program was to increase knowledge of the magnetosphere, interplanetary space, and the interactions between them.

The original mission objectives were:

  •  Investigate solar-terrestrial relationships at the outermost boundaries of the earth’s magnetosphere.
  • Examine in detail the structure of the solar wind near the earth.
  • Examine the shock wave boundary between the solar wind and the earth.
  • Investigate motions of, and mechanisms operating in, the plasma sheets.

The ISEE-3, the one of interest today, had an extensive array of experiments, designed to probe solar emissions and to gauge the effect of these emissions on the Earth’s magnetosphere.   Figure 2 shows a graphic of the ISEE-3 spacecraft:

Figure 2: The ISEE-3 Spacecraft
Figure 2: The ISEE-3 Spacecraft

ISEE-3 s a spin stabilized spacecraft and was built by Fairchild Space in Maryland (now Orbital Sciences Corporation).  Look at the graphic above and you will see that the 3D radio mapping antenna in the radial axis is 92 meters across from tip to tip!  Figure 3 is the vehicle in testing and a graphic of it in space:

Figure 3: ISEE-3 In Testing and a Graphic of its 1985 Comet Flyby
Figure 3: ISEE-3 In Testing and a Graphic of its 1985 Comet Flyby

Table 1 shows the instruments for ISEE-3 and their operational status as of the last substantial contact in 1999:

Table 1: ISEE-3 Instruments, the Principal Investigators, and the Last Known State
Table 1: ISEE-3 Instruments, the Principal Investigators, and the Last Known State

In short, this is an incredibly capable spacecraft.  If that was it, it would be an interesting story.  However, this is just the beginning.

The ISEE-3 Extended Mission Turns into ICE

Most spacecraft in this era were not really meant for extended operations beyond a few years (Voyager 1 and 2 being the obvious exceptions).  The primary mission of the ISEE-3 spacecraft was three years.  The ISEE trio were designed to operate through solar cycle 21 maximum and all three operated brilliantly.  These were the first spacecraft dedicated to the study of heliophysics, a term coined in 1981 based upon the discoveries of the ISEE satellites.  A NASA Technical Reports Server ( search turns up dozens of scientific papers, almost all breaking new ground in the emerging discipline of solar/terrestrial physics.

The ISEE-1 and 2 spacecraft were in low earth orbit, but ISEE-3 was placed into the Earth/Sun Lagrange point L1, the first spacecraft to be sent to that location.  This location, about 1 million kilometers closer to the sun than the Earth, is still gravitationally bound to the Earth and thus is “upstream” of the planet and in front of the bow shock of the Earth’s magnetosphere.  This is the perfect vantage point for a maximally instrumented spacecraft to observe solar phenomenon before it reaches the interface between the solar wind and the magnetosphere.

Dr. Robert Farquhar, ISEE-3 Flight Dynamics Manager comes up with a scenario that will take ISEE-3 out of the Earth-Moon system and take it to an asteroid flyby with comet Gaicobini-Zinner and then later to comet Halley.  Figure 4 shows the flight trajectory for this extended mission:

Figure 4: ISEE-3/ICE Extended Mission to World’s first Comet Flybys
Figure 4: ISEE-3/ICE Extended Mission to World’s first Comet Flybys

In order to obtain the energy necessary to escape Earth orbit for the comet flybys, the ISEE-3 spacecraft did multiple flybys of the Earth and a final flyby of the Moon.  This is an extremely delicate dance of orbital dynamics, trading of gravitational energy  for kinetic energy, a strategy developed by Dr. Farquhar and executed by his team.  When ISEE-3 did its final lunar flyby it was renamed the International Cometary Explorer (ICE). The renamed ICE spacecraft left the Earth/Moon system in September of 1982 (about the time I started bugging my boss).  On September 11, 1985 ICE passed through the tail of comet Gaicobini-Zinner at a distance of less than 8,000 kilometers, a masterful feat of celestial navigation.  Figure 5: shows the encounter:

Figure 5: ISEE-3/ICE Passes the Tail of Comet Gaicobini-Zinner Sept 11, 1985
Figure 5: ISEE-3/ICE Passes the Tail of Comet Gaicobini-Zinner Sept 11, 1985

ICE used its full suite of instruments during this pass and had the first instrumental confirmation that a comet perturbs the solar wind and the  magnetic field.  Again, a search of the NASA Technical Reports Server finds dozens of papers about this flyby and the next one at comet Halley.  Figure 6 shows the Halley and Gaicobini-Zinner flyby:

Figure 6: Two Comet Flyby’s By ISEE-3/ICE Spacraft in Heliocentric Orbit
Figure 6: Two Comet Flyby’s By ISEE-3/ICE Spacraft in Heliocentric Orbit

The illustration in figure 6 is relative to a fixed Sun-Earth line, essentially an inertial point in space.  The flyby of Halley’s comet was from a further distance of about 21 million kilometers.  Even at this distance the sensitive instruments on ICE detected the influence of the comet on the surrounding solar wind and magnetic field.  After the flybys ICE was tasked to do complimentary studies of the interplanetary solar wind, magnetic fields, and coronal mass ejections in concert with the NASA/ESA Ulysses spacecraft, that had been slung into a solar polar orbit by a close flyby of Jupiter.

After these flybys of two comets and the solar mission by this veteran spacecraft, Bob Farquhar’s flight dynamic guys had one more trick up their sleeves, and it was a doozy.

ICE/ISEE-3 Returns to the Earth in 2014

Figure 7 shows the final tour-de-force genius of the ICE navigation team:

Figure 7: ICE Trajectory from April 1986 Through August 2014
Figure 7: ICE Trajectory from April 1986 Through August 2014


The above illustration shows the orbital trace of ICE/ISEE-3 from a fixed Sun-Earth line.  Each loop represents each time the ICE spacecraft passe by the Earth.  It is in a 355 day solar orbit so ICE “laps” Earth in those number of days.  The orbit of ICE is slightly eccentric orbit with an aphelion (furthest distance from the sun) of 1.03 AU, and a perihelion (closest to the sun) of 0.93 AU.  What this does is to set ICE up for an encounter with the Earth, a lunar flyby, on August 10th of this year.

The Return and the Dilemma

On March 2nd  2014 a group of amateur radio satellite operators at AMSAT-DL in Germany heard the ICE spacecraft carrier, that had been left on intentionally by NASA.  Figure 8 shows the signal trace:

Figure 8: ICE S-Band Transponder First Reception (Down Converted)
Figure 8: ICE S-Band Transponder First Reception (Down Converted)

ISEE-3 ICE spacecraft signal spectrum recorded on March 2, 2014 at 1822 UT using the 20m dish antenna of Bochum Observatory, Germany. Range 43M km, azimuth 230°, elevation 49°. Average of 2 spectra spanning 2.1 seconds.

This is the reception report from the radio telescope at Bochum Observatory.  This was followed by a reception report from the Search for Extraterrestrial Intelligence (SETI) Allen array on March 20th.  This was followed by a reception report by Arecibo, the largest radio telescope in the world on April 9th of this year. Another report comes from Morehead State University, who we are working with in figure 9:

Figure 9: Morehead State Reception of the ICE Telemetry Transmitter 3/10/14
Figure 9: Morehead State Reception of the ICE Telemetry Transmitter 3/10/14

The dilemma is this, after all this time, after all the travels, and all of the planning by the ICE flight dynamics team, the one thing that they could not have foreseen in 1987 is that NASA would no longer be able to hear or to pay for the recovery of ICE.  Linked here is an article by Emily Lakdalla of the Planetary Society.  She copied a post by NASA Goddard on the subject.  It is reposted here:

Communication involves speaking, listening and understanding what we hear. One of the main technical challenges the ISEE-3/ICE project has faced is determining whether we can speak, listen, and understand the spacecraft and whether the spacecraft can do the same for us. Several months of digging through old technical documents has led a group of NASA engineers to believe they will indeed be able to understand the stream of data coming from the spacecraft. NASA’s Deep Space Network (DSN) can listen to the spacecraft, a test in 2008 proved that it was possible to pick up the transmitter carrier signal, but can we speak to the spacecraft? Can we tell the spacecraft to turn back on its thrusters and science instruments after decades of silence and perform the intricate ballet needed to send it back to where it can again monitor the Sun? The answer to that question appears to be no.

The transmitters of the Deep Space Network, the hardware to send signals out to the fleet of NASA spacecraft in deep space, no longer includes the equipment needed to talk to ISEE-3. These old-fashioned transmitters were removed in 1999. Could new transmitters be built? Yes, but it would be at a price no one is willing to spend. And we need to use the DSN because no other network of antennas in the US has the sensitivity to detect and transmit signals to the spacecraft at such a distance.

This effort has always been risky with a low probability of success and a near-zero budget. It is thanks to a small and dedicated group of scientists and engineers that we were able to get as far as we have. Thank you all very much.

Thus, with an impossible schedule, and without a budget, was born the ISEE-3 Reboot Project.

The ISEE-3 Reboot Project Begins

I have known about the ISEE-3/ICE spacecraft since my college days at the University of Alabama in Huntsville where I worked for the Center for Space Plasma and Aeronomic Research (CSPAR).  I have known Dr. Farquhar personally and by reputation for many years.  His work in orbital dynamics should have gotten him a Nobel Prize for its originality and brilliance.  When I read the above about them not having the equipment to talk to the spacecraft, it got me thinking and researching.

Our team has already successfully built a demodulator and software to recover images and data from the 1960’s Lunar Orbiter.  We have also recovered and modernized the infrared images from the Nimbus I,II, and III spacecraft of the 1960’s.  I had a vague notion that the ISEE-3 was not that much more advanced, so yet again our team started diving into the data and found that there was no computer on the spacecraft, which made things easier.  The modulation scheme is simpler than modern cell phones, which use a modern technique of using software for the modem, directly digitizing the signal and then processing it.  It seemed logical that this could be used for the ISEE-3 spacecraft.

Last year, as most readers who are aware of the Lunar Orbiter LOIRP project know, we crowd funded some significant money last year, about $68k, which spawned more private funding, which allowed us to make enough progress to get further funding that allowed us to completely finish the tape digitization portion of that project (we are still processing the final products).  Keith Cowing of NASA Watch was instrumental in making that happen.  These types of crowd funding projects require someone who really knows the media and very few people know more than Keith about modern online media Keith is also our co-lead on the LOIRP project.  So we started talking about what we would do if we were to do this project.  Keith is starting up a non profit STEM education project called Space College and this seemed to be a great project that we would use to involve students, volunteers and others attempt to recover the spacecraft.

Keith, being a former NASA civil servant and a long time pain in the rear/friend of the agency, knows everyone.  So, after it was determined by NASA GSFC that they could not do this, and after a teleconference where NASA headquarters told NASA GSFC, their contractors, and us that there was no money for any recovery effort, we started another crowd funding effort on Rockethub.  Things have started moving since then, beginning with panic.  Why, because we only have a short amount of time to make this happen!  We are fortunate that in two weeks we have raised over $51k of our $125k goal, but that is not where the panic is.

A question that you might have is why do this, what is going to come from it if I give a bit of my hard earned money to support it?  The long term answer is that we want to put it back into Earth Orbit, turn the science instruments on, and have it be an open science data source, used for STEM education, amateur radio solar predictions, and for science about the sun.  It is also an incredible technical challenge for as far as we know, no private entity has ever commanded, communicated with, and returned to earth orbit a spacecraft!  It is also a testament to the foresight of Dr. Farquhar and his team that deserves recognition.  Here is a list of firsts for the ISEE-/ICE spacecraft:

  • First Mission to a Libration Point
  • First Mission to Use a Suite of Instruments across the electromagnetic spectrum to measure the dynamics of the magnetosphere between the Earth and sun during a solar maximum.
  • First Lunar Flyby for Gravity Assist to an Interplanetary Trajectory
  • First Comet Flyby (1985)
  • Second Comet Flyby (1986)
  • 36 Year Trajectory to Return to Earth (2014)

This is a truly historic spacecraft and to not try and save it to me is an engineering and science tragedy that offends my engineering sensibility. Here simply is the problem in Figure 10:

Figure 10: Range from the Earth of the ICE/ISEE-3 Spacecraft
Figure 10: Range from the Earth of the ICE/ISEE-3 Spacecraft

In looking at figure 10 you see as we get closer to the date of the perigee pass around the Earth, the distance continues to decrease.  The problem is that no matter how good those guys were in doing the maneuvers in the 1980’s, it is not perfect and will not result in a capture into Earth orbit.  Thus we have to fire the thrusters of the spacecraft by late June or there will not be enough fuel left to make the course correction to put it into a permanent earth orbit.  Thus, Isaac Newton is driving this bus and unless we change the course, the spacecraft will drift back into planetary space, not to return until 2029.

ISEE-3 Reboot Technical Issues and Our Process

There are several questions that must be answered in the ISEE-3 Reboot Project.

–      Is the Spacecraft Still Alive (verified yes)

–      Can We Talk to it? (Under Development)

–      Can the Propulsion System Be Activated (Working on it)

–      Can the Spacecraft Be Put Back Into A Stable Earth Orbit (Depends on the Previous Questions)

We have made a lot of organizational and technical progress toward answering these questions.  In summary, we have the folks at Morehead State University in Kentucky working with us on the project.  We have also gained the agreement from Arecibo that they will listen to the spacecraft more for us and that if we send them a transmitter that is easy to set up, that they will transmit our command signals to the spacecraft.  This is beyond valuable and means that we don’t really have to worry that much about link margin but can just blast a signal that way, especially as the range is decreasing every day.

Our plan for the recovery is this.

  1. Secure and send 200W transmitter to Arecibo.
  2. Arecibo sends simple audio tone to the spacecraft to ascertain whether or not the ranging function was left on.
  3. Develop a single manual command that can be fed into the HP synthesizer at Arecibo to turn the Engineering Telemetry function on.
  4. Ascertain the health of the spacecraft and debug the telemetry recording and display system.
  5. Figure out how to do the ranging, we  have a team working this right now.
  6. Update any trajectory (Dave Dunham/Farquhar).
  7. Install 700 Watt transmitter at Morehead State and test as the spacecraft gets closer.
  8. Command the burn either at Morehead or Arecibo.
  9. Pray
  10. Do ranging after the spacecraft is captured into Earth orbit for final orbital insertion burns (much easier to do with reduced range).
  11. Put into final orbit and re-commission the science experiments.

We have several groups of people working with us right now, almost everyone a volunteer at this point.  We still have a couple of really big problems (well maybe four or five) to solve, the ranging seeming to be the biggie.

We will have a lot more press releases and blog posts out over the next few days but I wanted to give everyone the highlights.  We are going to setup our mission operations center at a location that I can’t disclose until some paperwork is finally signed but it is in progress.  Really all we are going to do is to revive the command and telemetry consoles.  We are going to display in real time the propulsion system, the attitude determination and control system, as well as the power system.  We have several analyses done, documents scanned, data transferred from archived pdf’s to excel, and many other things.  We have an incredible bunch of people helping us but we need one thing more…


As I stated earlier, we are right now an almost completely volunteer project with the exception of a couple of my engineers at my small company who are working on critical aspects of the project.  We are raising $125k that we hope will get us to the point where we get the steps outlined above done.  If we can do this, we will have an open source, publically accessible satellite data stream of the first open source satellite above Low Earth Orbit.  Personally I am already learning boatloads about how to operate and control an interplanetary satellite.  I am still learning after all these years and the design of the ISEE-3 has some incredibly interesting features that I think are valuable to spacecraft design today that we may use.


If we don’t fire the thrusters by late June, figure 11 is what the orbit will look like:

Figure 11: The Fate of ICE/ISEE-3 If We Fail
Figure 11: The Fate of ICE/ISEE-3 If We Fail

I can tell you that, from being completely panicked that this was going to be darn near impossible, it is just going to be very darn hard.  It will be impossible without your financial help.  Here is the trajectory in figure 12 if we save the bird:

Figure 12: ISEE-3R Flight Path Baseline If We are Successful
Figure 12: ISEE-3R Flight Path Baseline If We are Successful

Help us be successful.  What I would like to ask of this community is that 300 people give $100 each to the project.  For those who cannot do that, please do what you can.  I can tell you though, that if the 300 give $100 the rest will come.  It is just how the momentum thing works in crowd funding.  I know that this is hard earned money and that this is a science mission.  However, it is also about bringing a team of people together to do what other people say is impossible.  Going back to my opening, I did a lot of research on this, and by standing on the shoulders of giants like Bob Farquhar, Dave Dunham, and the rest of the ISEE-3/ICE crew, we can do this.  NASA is providing moral support and documents and have indicated their positive support for our effort.  More to come soon, so again thanks and I look forward to giving everyone more reports soon!

Oh, by the way, here is the link to our crowd funding site:



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