International Cometary Explorer

International Cometary Explorer

Artist rendering of ICE
Names International Sun/Earth Explorer 3
Explorer 59
Mission type Magnetospheric research
ISEE-3: Earth/Moon L1 orbiter
ICE: 21P/G-Z & Halley fly-by
Operator NASA, ESA
COSPAR ID 1978-079A
SATCAT № 11004
Mission duration 18 years, 8 months and 23 days
Spacecraft properties
Manufacturer Fairchild Industries
Launch mass 390 kg (860 lb)
Power 173 watts
Start of mission
Launch date 15:12:00, August 12, 1978
Rocket Delta 2914 #144
Launch site CCAFS SLC-17B
End of mission
Disposal Contact suspended
Deactivated May 5, 1997
Orbital parameters
Reference system Heliocentric
Eccentricity 0.05
Perihelion 0.93 AU
(139,000,000 km; 86,400,000 mi)
Apohelion 1.03 AU
(154,000,000 km; 95,700,000 mi)
Inclination 0.1°
Period 355 days
Epoch March 28, 1986, 00:00:00 UTC
Explorers program
← Explorer 58 Explorer 60 →

The International Cometary Explorer (ICE) spacecraft (designed and launched as the International Sun/Earth Explorer 3 (ISEE-3) satellite), was launched August 12, 1978, into a heliocentric orbit. It was one of three spacecraft, along with the mother/daughter pair of ISEE-1 and ISEE-2, built for the International Sun-Earth Explorer (ISEE) program, a joint effort by NASA and ESRO/ESA to study the interaction between the Earth's magnetic field and the solar wind.

ISEE-3 was the first spacecraft to be placed in a halo orbit at the L1 Earth-Sun Lagrangian point. Renamed ICE, it became the first spacecraft to visit a comet, passing through the plasma tail of Comet Giacobini-Zinner within about 7,800 km (4,800 mi) of the nucleus on September 11, 1985.[1]

NASA suspended routine contact with ISEE-3 in 1997, and made brief status checks in 1999 and 2008.[2][3]

On May 29, 2014, two-way communication with the spacecraft was reestablished by the ISEE-3 Reboot Project, an unofficial group[4] with support from the Skycorp company.[5][6][7] On July 2, 2014, they fired the thrusters for the first time since 1987. However, later firings of the thrusters failed, apparently due to a lack of nitrogen pressurant in the fuel tanks.[8][9] The project team initiated an alternative plan to use the spacecraft to "collect scientific data and send it back to Earth,"[10] but on September 16, contact with the probe was lost.[11]

Original mission: International Sun/Earth Explorer 3 (ISEE-3)

International Sun/Earth Explorers orbits
ICE mission
Top-down view of the orbit of ICE relative to the inner Solar System in and after 2009.

ISEE-3 carries no cameras; instead, its instruments measure energetic particles, waves, plasmas, and fields.

ISEE-3 originally operated in a halo orbit about the L1 Sun-Earth Lagrangian point, 235 Earth radii above the surface (about 1.5 million km, or 924,000 miles). It was the first artificial object placed at a so-called "libration point", proving that such a suspension between gravitational fields was possible. It rotates at 19.76 rpm about an axis perpendicular to the ecliptic, to keep it oriented for its experiments, to generate solar power and to communicate with Earth.

The purposes of the mission were:

Second mission: International Cometary Explorer

On June 10, 1982, after completing its original mission, ISEE-3 was renamed the International Cometary Explorer (ICE) and given a new mission: to study the interaction between the solar wind and a cometary atmosphere.

On September 1 of that year, a thruster burn was used to knock it loose from its L1 halo orbit. Following a flyby of the Moon on October 26, and a long fly-around of Earth, it entered a Lissajous orbit at the Sun–Earth L2 Lagrangian point. Its last and closest pass over the Moon, on December 22, 1983, was a mere 119.4 km (74 mi) above the Moon's surface. By the beginning of 1984, ICE was in heliocentric orbit.

Giacobini-Zinner encounter

Its new orbit put it ahead of the Earth on a trajectory to intercept Comet Giacobini-Zinner. On September 11, 1985, the craft passed through the comet's plasma tail.

Halley encounter

ICE transited between the Sun and Comet Halley in late March 1986, when other spacecraft were near the comet on their early-March comet rendezvous missions. (This "Halley Armada" included Giotto, Vega 1 and 2, Suisei and Sakigake.) ICE flew through the tail; its minimum distance to the comet nucleus was 28 million km[12] (for comparison, the Earth's minimum distance to Comet Halley in 1910 was 20.8 million km[13]).

Heliospheric mission

An update to the ICE mission was approved by NASA in 1991. It defines a heliospheric mission for ICE consisting of investigations of coronal mass ejections in coordination with ground-based observations, continued cosmic ray studies, and the Ulysses probe. By May 1995, ICE was being operated under a low duty cycle, with some data-analysis support from the Ulysses project.

End of mission

On May 5, 1997, NASA ended the ICE mission, leaving only a carrier signal operating. The ISEE-3/ICE downlink bit rate was nominally 2048 bits per second during the early part of the mission, and 1024 bit/s during the Giacobini-Zinner comet encounter. The bit rate then successively dropped to 512 bit/s (on December 9, 1985), 256 bit/s (on January 5, 1987), 128 bit/s (on January 24, 1989) and finally to 64 bit/s (on December 27, 1991). Though still in space, NASA donated the craft to the Smithsonian Museum.[14]

By January 1990, ICE was in a 355-day heliocentric orbit with an aphelion of 1.03 AU, a perihelion of 0.93 AU and an inclination of 0.1 degree.

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. A status check revealed that all but one of its 13 experiments were still functioning, and it still had enough propellant for 150 m/s (490 ft/s) of Δv.

It was determined to be possible to reactivate the spacecraft in 2014,[15] when it again made a close approach to Earth, and scientists discussed reusing the probe to observe more comets in 2017 or 2018.[16]

Reboot effort

Sometime after NASA's interest in the ICE waned, others realized that the spacecraft might be steered to pass close to another comet. A team of engineers, programmers, and scientists began to study the feasibility and challenges involved.[7]

In April 2014, its members formally announced their intentions to "recapture" the spacecraft for use, calling the effort the ISEE-3 Reboot Project. 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."[17]

On May 15, the project reached its crowdfunding goal of US$125,000 on RocketHub, which was expected to 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.[18] The project then set a "stretch goal" of $150,000, which it also met with a final total of $159,502 raised.[19]

The project members were working on deadline: if they got the spacecraft to change its orbit by late May or early June 2014, or in early July by using more fuel, it could use the Moon's gravity to get back into a useful halo orbit.[20][21][22]

Replacing lost hardware

Earlier in 2014, officials with the Goddard Space Flight Center said the Deep Space Network equipment necessary to transmit signals to the spacecraft had been decommissioned in 1999, and was too expensive to replace.[23] However, project members were able to find documentation for the original equipment and were able to simulate the complex modulator/demodulator electronics using modern software defined radio (SDR) techniques and open-source programs from the GNU radio project. They obtained the needed hardware, an off-the-shelf SDR transceiver and power amplifier,[24] and installed it on the 305-meter Arecibo dish antenna on May 19, 2014.[24][25] Once they gained control of the spacecraft, the capture team planed to shift the primary ground station to the 21-meter dish located at Kentucky's Morehead State University Space Science Center.[24] The 20-meter dish antenna in Bochum Observatory, Germany, would be a support station.[24]

Although NASA was 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.[26]

Contact reestablished

On May 29, the reboot team successfully commanded the probe to switch into Engineering Mode to begin to broadcast telemetry.[27][28]

On June 26, project members using the Goldstone Deep Space Communications Complex DSS-24 antenna achieved synchronous communication and obtained the four ranging points needed to refine the spacecraft's orbital parameters.[29] The project team received approval from NASA to continue operations through at least July 16, and plan to attempt the orbital maneuver in early July.[21][30]

On July 2, the reboot project fired the thrusters for the first time since 1987. They spun up the spacecraft to its nominal roll rate, in preparation for the upcoming trajectory correction maneuver in mid-July.[31][32]

On July 8, a longer sequence of thrusters firings failed, apparently due to loss of the nitrogen gas needed to pressurize the fuel tanks.[8][9][10]

On July 24, the ISEE-3 Reboot Team announced that all attempts to change orbit using the ISEE-3 propulsion system had failed. Instead, the team said, the ISEE-3 Interplanetary Citizen Science Mission would gather data as the spacecraft flies by the Moon on August 10 and enters a heliocentric orbit similar to Earth's. The team began shutting down propulsion components to maximize the electrical power available for the science experiments.[33]

On July 30, the team announced that it still planned to acquire data from as much of ISEE-3's 300-day orbit as possible. With five of the 13 instruments on the spacecraft still working, the science possibilities included listening for gamma ray bursts, where observations from additional locations in the Solar System can be valuable. The team was also recruiting additional receiving sites around the globe to improve diurnal coverage, in order to upload additional commands while the spacecraft is close to Earth and later to receive data.[34]

On August 10 at 18:16 UTC, the spacecraft passed about 15,600 km (9,700 mi) from the surface of the Moon. It will continue in its heliocentric orbit, and will return to the vicinity of Earth in 17 years.[35]

Contact lost

On September 25, the Reboot team announced that contact with the probe was lost on September 16. It is unknown whether contact can be reestablished because the probe's exact orbit is uncertain. The spacecraft's post-lunar flyby orbit takes it further from the Sun, causing electrical power available from its solar arrays to drop. Reduced power could have caused the craft to enter a safe mode, from which it may be impossible to awaken without the precise orbital location information needed to point transmissions at the craft.[11]

Spacecraft design

The ISEE-3 (later ICE), undergoing testing and evaluation.

The ICE spacecraft is a barrel-like cylindrical shape covered by solar panels. Four long antennas protrude equidistant around the circumference of the spacecraft, spanning 91 metres (299 ft).[36] It has a mass of 390 kg (860 lb) and can generate a nominal power of 173 watts.

Payload

ICE carries 13 scientific instruments to measure plasmas, energetic particles, waves, and fields. As of May 2014, all but one are thought to be functional. It does not carry a camera or imaging system. Its detectors measure high energy particles such as X and gamma rays, solar wind, plasma and cosmic particles. A data handling system gathers the scientific and engineering data from all systems in the spacecraft and formats them into a serial stream for transmission. The transmitter output power is five watts.

Scientific payload and experiments

[37]

Publications

References

  1. ↑ Stelzried, C.; Efron, L.; Ellis, J. (July–September 1986). Halley Comet Missions (PDF) (Report). NASA. pp. 241–242. TDA Progress Report 42-87.
  2. ↑ Robertson, Adi (May 23, 2014). "Spaceship come home: can citizen scientists rescue an abandoned space probe?". The Verge. Retrieved June 26, 2014.
  3. ↑ McKinnon, Mika (April 15, 2014). "Can This 1970s Spacecraft Explore Again?". io9.com. Retrieved June 26, 2014.
  4. ↑ "We do NOT like...". Twitter.com. June 25, 2014. Retrieved June 25, 2014.
  5. ↑ Geuss, Megan (May 29, 2014). "ISEE-3 spacecraft makes first Earth contact in 16 years". Ars Technica. Retrieved May 31, 2014.
  6. ↑ Matheson, Dan (May 2014). "Citizen-scientists look to reboot 35-year-old spacecraft". CTV News. Retrieved May 31, 2014.
  7. ↑ 7.0 7.1 Chang, Kenneth (June 15, 2014). "Calling Back a Zombie Ship From the Graveyard of Space". The New York Times. Retrieved June 15, 2014.
  8. ↑ 8.0 8.1 McKinnon, Mika (July 10, 2014). "Distributed Rocket Science is a Thing Now - ISEE-3 Status Report (July 10, 2014)". ISEE-3 Reboot Project. Retrieved July 12, 2014.
  9. ↑ 9.0 9.1 Cowing, Keith (July 18, 2014). "OpEd - Lost and Found in Space - Rebooting ISEE-3: Space for All". New York Times. Retrieved July 18, 2014.
  10. ↑ 10.0 10.1 Chang, Kenneth (July 9, 2014). "Space Probe Might Lack Nitrogen to Push It Home". The New York Times. Retrieved July 10, 2014.
  11. ↑ 11.0 11.1 "ISEE-3 is in Safe Mode". Space College. 25 September 2014. The ground stations listening to ISEE-3 have not been able to obtain a signal since Tuesday the 16th
  12. ↑ Murdin, Paul, ed. (November 2000). "International Cometary Explorer (ICE)". Encyclopedia of Astronomy and Astrophysics. IOP Science. Bibcode:2000eaa..bookE4650.. doi:10.1888/0333750888/4650.
  13. ↑ Reddy, Francis. "Comets". Astronomy.com. Archived from the original on June 7, 2010. |chapter= ignored (help)
  14. ↑ Thomson, Iain (April 24, 2014). "Privateers race to capture forgotten NASA space probe using crowdsourced cash". The Register. Retrieved May 20, 2014.
  15. ↑ Greene, Nick. "International Sun-Earth Explorer 3 - International Cometary Explorer". About.com. Retrieved June 26, 2014.
  16. ↑ Lakdawalla, Emily (October 3, 2008). "It's Alive!". The Planetary Society.
  17. ↑ Cowing, Keith (April 14, 2014). "ISEE-3 Reboot Project (IRP)". Space College.
  18. ↑ Cowing, Keith (May 15, 2014). "ISEE-3 Reboot Project Passes Funding Goal". Space College.
  19. ↑ Cowing, Keith (May 23, 2014). "ISEE-3 Reboot Project Completes Crowdfunding Drive". Space College.
  20. ↑ Greenfieldboyce, Nell (March 18, 2014). "Space Thief Or Hero? One Man's Quest To Reawaken An Old Friend". National Public Radio.
  21. ↑ 21.0 21.1 "A Retired Satellite Gets Back To Work". NPR Here & Now. 2014-06-27. Retrieved 2014-06-27.
  22. ↑ Wingo, Dennis (May 1, 2014). "ISEE-3 Reboot Project Technical Update 1 May 2014". Space College.
  23. ↑ Lakdawalla, Emily (February 7, 2014). "ICE/ISEE-3 to return to an Earth no longer capable of speaking to it". The Planetary Society.
  24. ↑ 24.0 24.1 24.2 24.3 Cowing, Keith (May 15, 2014). "ISEE-3 Reboot Project Status and Schedule for First Contact". Space College. Retrieved May 20, 2014.
  25. ↑ "ISEE-3 Reboot Project by Space College, Skycorp, and SpaceRef". RocketHub. May 20, 2014. Retrieved May 20, 2014.
  26. ↑ Cole, Steve; Wingo, Dennis (May 21, 2014). "NASA Signs Agreement with Citizen Scientists Attempting to Communicate with Old Spacecraft" (Press release). NASA.
  27. ↑ Neuman, Scott (May 29, 2014). "After Decades Of Silent Wandering, NASA Probe Phones Home". National Public Radio.
  28. ↑ "Citizen Scientists Successfully Communicate with Spacecraft". NASA. May 30, 2014. Retrieved May 31, 2014.
  29. ↑ Cowing, Keith (June 26, 2014). "ISEE-3 Status 26 June 2014: DSN Ranging Success". Space College. Retrieved June 26, 2014.
  30. ↑ Cowing, Keith (June 27, 2014). "ISEE-3 Status 27 June 2014: Another DSN Ranging Success - Space College". Space College.
  31. ↑ "ISEE-3 Propulsion System Awakens at 11th Hour". SpaceNews.com. 2014-07-03. Retrieved 2014-07-03.
  32. ↑ "ISEE-3 Engines Fired For Spin-Up". Space College. 2014-07-02. Retrieved 2014-07-02.
  33. ↑ http://spacecollege.org/isee3/announcing-the-isee-3-interplanetary-citizen-science-mission.html
  34. ↑ Vintage NASA Spacecraft to Tackle Interplanetary Science, Elizabeth Howell, Space.com, July 30, 2014
  35. ↑ Chang, Kenneth (August 8, 2014). "Rudderless Craft to Get Glimpse of Home Before Sinking Into Space's Depths". The New York Times. Retrieved August 9, 2014.
  36. ↑ Cowing, Keith (June 7, 2014). "What ISEE-3 Really Looks Like". Space College.
  37. ↑ "ISEE 3: Experiment Search Results". NASA.

External links

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