How to Rescue a Long-Lost Spaceship”“in 8 Steps

ISEE-3 has been left for dead for years. Tuesday, it starts its journey home.

National Journal
Alex Brown
July 8, 2014, 7:41 a.m.

In 1999, as the world was bra­cing for Y2K, NASA trashed some old trans­mit­ters it had used to talk to space­ships that were no longer in use.

But one of those space­ships for­got to die.

ISEE-3 was launched in 1978, con­duct­ing ground­break­ing mis­sions that in­cluded stud­ies of sol­ar wind and comet flybys. In 1997, it was left to sail away, 850 pounds of met­al float­ing through the junk­yard of space. But someone neg­lected to turn it off.

In 2008, NASA real­ized the poor satel­lite was circ­ling the sun, still wait­ing for or­ders from its home plan­et. But those or­ders nev­er came. Even though sci­ent­ists could listen to ISEE-3—de­term­in­ing 12 of its 13 in­stru­ments were still work­ing—they had no way of telling it what to do next. It spoke a lost lan­guage.

Next month, ISEE-3 will fi­nally come home, its first vis­it in 30 years (its slightly faster or­bit means it has done 31 laps of the Sun in the same time Earth has done 30). It would have been the per­fect chance to use the Earth’s grav­ity to send it on a new mis­sion. Every­one thought it was a lost op­por­tun­ity. ISEE-3 would miss Earth and sail right on by, float­ing farther and farther out of our reach.

Enter Sky­corp. The Cali­for­nia com­pany asked NASA to let it try to save ISEE-3. The agency had said earli­er that try­ing to re­build the ne­ces­sary trans­mit­ters wasn’t worth the in­vest­ment. With noth­ing to lose, NASA gave Sky­corp per­mis­sion to try to talk to its for­saken satel­lite.

If all goes ac­cord­ing to plan, ISEE-3 will steer with its thrusters Tues­day for the first time since Ron­ald Re­agan was in of­fice. Sky­corp hopes to steer it in­to Earth’s or­bit and again use it to take sci­entif­ic meas­ure­ments. It plans to live-share the data it col­lects with the pub­lic. Here’s how their plan has worked so far.

1. Get some money. Be­fore Sky­corp could make a bid to save the space­ship, it needed fund­ing. Thanks to satel­lite en­thu­si­asts on the In­ter­net, it was able to raise well in ex­cess of its $125,000 goal.

2. Find a part­ner. To com­mu­nic­ate with ISEE-3, Sky­corp needed trans­mit­ters that no longer ex­ist. Rather than dig­ging out old manu­als and re­build­ing the trans­mit­ters, the com­pany ap­proached Ettus Re­search. Ettus uses what’s known as soft­ware-defined ra­dio, which uses pro­cessors to rep­lic­ate the func­tions of many dif­fer­ent types of hard­ware. Ettus soft­ware “emu­lates all of the hard­ware equip­ment NASA used to have,” said Sky­corp CEO Den­nis Wingo.

3. Get per­mis­sion. On May 21, NASA gave the go-ahead for Sky­corp to try to save its satel­lite. The agency agreed to share tech­nic­al data with Sky­corp, cit­ing the com­pany’s pledge to share its find­ings with the sci­entif­ic com­munity.

4. Es­tab­lish con­tact. Just a week after NASA handed over the keys to ISEE-3, Sky­corp made con­tact with the satel­lite and began giv­ing it com­mands—the first such com­mu­nic­a­tion in 16 years.

5. Find your satel­lite. Though the gen­er­al or­bit of ISEE-3 was well-known, sci­ent­ists were deal­ing with a 20,000 mile win­dow—some parts of that range would have the satel­lite on course to crash in­to the moon. Sky­corp’s first in­struc­tions to ISEE-3 were to turn on its tele­metry.

6. Give it dir­ec­tions. On Ju­ly 2, Sky­corp fired thrusters to speed up the satel­lite’s rate of spin. The course cor­rec­tions will put ISEE-3 in a bet­ter po­s­i­tion to com­mu­nic­ate with Earth.

7. Check your in­stru­ments. Once ISEE-3 is in a bet­ter com­mu­nic­a­tion spot, Sky­corp will run tests on its 13 in­stru­ments. For now, it’s at least get­ting data from some of them. The com­pany re­por­ted on Ju­ly 1 that the mag­ne­to­met­er had de­tec­ted a re­cent sol­ar event.

8. Fly home. The real test will come Tues­day, when en­gin­eers try to change the satel­lite’s tra­ject­ory and push it back in­to Earth or­bit. Dr. Robert Far­quhar, who co­ordin­ated the ship’s comet mis­sions, is over­see­ing the dir­ec­tion shift. Only a few days re­main to try, giv­en the ISEE-3’s or­bit and thrust ca­pa­city. And no one knows if the ship has leaked fuel or the en­gines still func­tion cor­rectly. But if everything works, Sky­corp will have suc­cess­fully saved a satel­lite from dec­ades of aim­less sol­ar wan­der­ing.

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