accomplished through a lot of team work, strong leadership
and generous support from the community at large
designed a deep-space uplink modulator in a couple of days,
products like the Ettus Research USRP, the open source SDR framework GNU Radio have made this exceedingly easy.
12 June 2014
telemetry from ISEE-3 indicating that its entire suite of science instruments is powered up and has been powered up since NASA last commanded the spacecraft many years ago
getting data back from the magentometer that indicates that science data is coming back
Just because an instrument is powered up doesn't mean that it is functioning normally
some of the ISEE-3 instruments had begun to fail or become partially functional as early as 1982
plans to briefly fire two of the spacecraft's thrusters on 21 June so as to spin it up from 19.16 rpm to the mission specification of 19.75 +/- 0.2 rpm
spin-up target is 19.733 rpm
This burn would utilize spin-up thrusters A and B
This optimal spin rate is required in order to properly fire the axial thrusters during the much longer trajectory correction maneuver (TCM) we need to perform to adjust the spacecraft's course
Original mission: International Sun/Earth Explorer 3 (ISEE-3)
to investigate solar-terrestrial relationships at the outermost boundaries of the Earth's magnetosphere
to examine in detail the structure of the solar wind near the Earth and the shock wave that forms the interface between the solar wind and Earth's magnetosphere
investigate motions of and mechanisms operating in the plasma sheets
continue the investigation of cosmic rays and solar flare emissions in the interplanetary region near 1 AU
Second mission: International Cometary Explorer
On June 10, 1982, after completing its original mission, ISEE-3 was repurposed. It was renamed the International Cometary Explorer (ICE)
The primary scientific objective of ICE was to study the interaction between the solar wind and a cometary atmosphere
a series of lunar orbits over the next 15 months. Its last and closest pass over the Moon, on December 22, 1983, was a mere 119.4 km above the Moon's surface. By the beginning of 1984, ICE was in heliocentric orbit
Giacobini-Zinner encounter
on a trajectory intercepting that of Comet Giacobini-Zinner.
On 11 September 1985, the craft passed through the plasma tail of Comet Giacobini-Zinner
ICE carried no cameras. It instead carried instruments for measurements of energetic particles, waves, plasmas, and fields
Halley encounter
transited between the Sun and Comet Halley in late March 1986, when other spacecraft
were in the vicinity of Comet Halley
ICE flew through the tail
Heliospheric mission
mission was approved by NASA in 1991
consisting of investigations of coronal mass ejections in coordination with ground-based observations
End of mission
On May 5, 1997, NASA ended the ICE mission, and ordered the probe shut down, with only a carrier signal left operating
Further contact
In 1999, NASA made brief contact with ICE to verify its carrier signal. On September 18, 2008
NASA, with the help of KinetX, located ICE using the Deep Space Network after discovering that it had not been powered off after the 1999 contact
status check revealed that all but one of its 13 experiments were still functioning, and it still has enough propellant
Reboot effort
A team webpage said, "We intend to contact the ISEE-3 (International Sun-Earth Explorer) spacecraft, command it to fire its engine and enter an orbit near Earth, and then resume its original mission...If we are successful we intend to facilitate the sharing and interpretation of all of the new data ISEE-3 sends back via crowd sourcing."
Sometime after NASA's interest in the ICE waned
A team of engineers, programmers, and scientists
realized that the spacecraft might be steered to pass close to another comet
began to study the feasibility and challenges involved
On May 15, 2014, the project reached its crowdfunding goal
which will cover the costs of writing the software to communicate with the probe, searching through the NASA archives for the information needed to control the spacecraft, and buying time on the dish antennas
The project then set a 'stretch' goal of $150,000
The project members are working on deadline: if they get the spacecraft to change its orbit by late May or early June 2014, it can use the Moon's gravity to get back into a useful halo orbit.
Earlier in 2014, officials with the Goddard Space Flight Center had said that the Deep Space Network equipment necessary to transmit signals to the spacecraft had been decommissioned in 1999, and that replacing it was not economically feasible
oject members obtained the needed hardware (power amplifier, modulator/demodulator[12]), and installed it on the 305-meter Arecibo dish antenna on May 19, 2014
Although NASA is not funding the project, it made advisors available and gave approval to try to establish contact
On May 21, 2014, NASA announced that it had signed a Non-Reimbursable Space Act Agreement with the ISEE-3 Reboot Project
"This is the first time NASA has worked such an agreement for use of a spacecraft the agency is no longer using or ever planned to use again," officials said
The final state of the spacecraft before was to have both of the transponders transmitters active and that is what people around the world have been tracking.
the spacecraft is set up with a lot of redundancy so you can use either transponder A or B to send telemetry or range
We tried several times to command the spacecraft's B transponder at 2041.9479 MHz into the mode where it normally sends engineering telemetry
did not work
Then we tried the same process on transponder A
modulation from the output of the telemetry system
The initial command was just to turn engineering telemetry on at 512 bits/second. This was successful.
successfully commanded the spacecraft into engineering telemetry mode.
initial verification
later
through the A transponder's receiver we commanded through the B transponder's command decoder to output engineering telemetry through transponder B's transmitter
verified so far the following systems on the spacecraft
1. Transponder A receiver
2. Transponder A's Command Decoder and Data Handling Unit
3. Transponder B's Command Decoder and Data Handling Unit
tried to command the spacecraft into 64 bits/second mode, which was a mode that is much more complicated to set up and we did not get working successfully during the limited time that the spacecraft is visible from Arecibo
need to do this so that the smaller dishes at Morehead State and Bochum will have a positive signal margin so that we can record several hours of data
neither of the ISEE-3/ICE receivers had met their specification in testing
for -120 dbm sensitivity
receiver A was tested at about -114 dbm, and Receiver B at -111 dbm
after our end to end systems test we had an earthquake
how observations could be affected by vibrations in the dome structure as it translates during an observation and then that happened
later processed our first day's data dump from the spacecraft and we received 49 full frames of data at a bit rate of 512 bits/second
there were no errors on the downlink
milestones related to commanding and receiving data
1. Successful commanding multiple times of ISEE-3/ICE
2. Received engineering telemetry from both data multiplexing units on the spacecraft
3. Successful demodulation on the ground of the received data, through the output of bits
4. Verification of good data at 512 bits/sec, including frame synchronization, correct number of bits/frame, and with no errors, showing a very strong 30+ db link margin through Arecibo
If we can maneuver the spacecraft by June 17th we get the very small delta V number
this starts to climb rapidly as the spacecraft gets closer to the moon
reliminary evaluation of the spacecraft and its systems so as to better understand it.
Most of the best information that we have been able to find has been from the people who worked on the project in the 1980's when the spacecraft was fully operational
have also obtained several documents from NASA as part of the development of our Space Act Agreement
Since there is no computer on board the ISEE-3 spacecraft our task is actually much easier since we are going to be directly commanding various subsystems
This is an ongoing process and we have, as usual, dug some of the pertinent information out of 35 year old IEEE or AIAA papers that are publicly available
The ISEE-3/ICE spacecraft was never really designed to be an interplanetary cruiser and thus the thrusters on board are very small
estimate that if we wait until mid-June to do the course correction that it will take 17 hours of thrusting to get the course change of about 40 meters/second that we will need at that time
The IEEE-3 spacecraft was launched on 12 August 1978
Originally the mission was cooperative effort between NASA and ESRO/ESA to study the interaction between the Earth’s magnetic field and the solar wind.
On 10 June 1982 IEEE-3 became the International Cometary Explorer with the primary scientific objective of ICE was to study the interaction between the solar wind and a cometary atmosphere
The mission required the spacecraft to leave the Earth/moon system and orbit around the sun instead
After encounters with comet Giacobini-Zinner in 1985 and the famous Halley’s comet in 1986 and the study of CME’s from the sun in 1991, the “plug” was pulled in the spacecraft on 5 May 1997
The team successfully established contact that afternoon — notwithstanding a minor earthquake in the area — at a heart-thumping transmission rate of 512 bits per second.
approval from NASA to attempt contact, and that go-ahead came on May 29th
The next task will be looking at the propulsion system and making sure they can actually fire the engines for a trajectory correction maneuver (TCM), currently targeted for June 17.