• PROJECTS
  • Advocacy and Education
  • Extrasolar Planets
  • Innovative Technologies
  • International Mission Participation
  • Mars Exploration
  • Near Earth Objects
    • Apophis Mission Design Competition
      • Project Updates
      • Competition Rules
      • Winning Proposals
      • Winning Teams
      • Judging Panel
      • Press Room
      • The Tunguska Event
    • Shoemaker NEO Grants
  • Search for Extraterrestrial Life
  • Past Projects
• THE PLANETARY REPORT
• PLANETARY RADIO
• BLOG
• SOCIETY UPDATES

browse projects: Apophis Mission Design Competition Carl Sagan Fund for the Future Catalog of Exoplanets FINDS Exo-Earths International Year of Astronomy 2009 LIFE Experiment: Phobos Messages from Earth Observing Earth Pioneer Anomaly Planetary Microphones SETI Optical Telescope SETI Radio Searches SETI@home Shoemaker NEO Grants Solar Sailing Space Advocacy Space Information

browse space topics: 2001 Mars Odyssey Asteroids and Comets Cassini-Huygens Chandra X-Ray Observatory Chandrayaan-1 Chang'e 1 Compare the Planets Dawn Deep Impact Earth Extrasolar Planets Genesis Hayabusa (MUSES-C) Hubble Space Telescope Jupiter Kaguya (SELENE) Lunar Reconnaissance Orbiter (LRO) Mars Mars Exploration Rovers Mars Express Mars Global Surveyor Mars Reconnaissance Orbiter Mars Science Laboratory Mercury MESSENGER Moon Near Earth Objects Neptune New Horizons Past Missions Phoenix Planetary Analogs Planetary Exploration Timelines Pluto and Charon Private Missions Rosetta Saturn Search for Extraterrestrial Intelligence SMART-1 SOHO Space Imaging Spitzer Space Telescope Stardust Trans-Neptunian Objects Ulysses Uranus Venus Venus Express Voyager Weekly Planetary Radio Trivia Contest

Projects: Apophis Mission Design Competition

The Winning Mission Proposals

The first, second, and third prize winners in The Planetary Society's Apophis Mission Design Competition shared a similar approach to solving the tracking challenge: send an instrumented orbiter to rendezvous with the asteroid and analyze its surface and shape up close.  Once the initial survey period is complete, the orbiter would position itself in a stable orbit, after which radio tracking of the spacecraft from Earth would provide the necessary precision of the measurements of Apophis' position.  The proposers did not consider it sufficient just to track the asteroid, skipping any initial survey, because, they argued, Apophis' shape and surface properties produce important influences on its future orbit due to the Yarkovsky effect.

However, the proposers differed markedly in how thorough a survey of the asteroid they planned to perform, which directly influenced the size, cost, and complexity of the proposed mission.  The winning proposal, Foresight, is a low-cost, conventionally propelled orbiter with only two instruments and a single-band radio tracking system.  The second- and third- prize winners propose increasingly complex missions, with increasing costs.

Winning Proposals at a Glance

	Foresight First prize	A-Track Second prize	APEX Third prize
	Click to enlarge >	Click to enlarge >	Click to enlarge >
Cost (millions)	$137.2	$387.2	$493.8
Size	0.85 x 0.85 x 0.7 m	1.7 x 1.7 x 1.8 m	1.3 x 1.3 x 1.3 m
Launch mass (dry)	100.2 kg	540.2 kg	657.6 kg
Propulsion	Chemical	Chemical	Solar electric
Solar panel size	1.2 m2	6 m2	12 m2
Instruments	-Camera -Laser altimeter -X-band tracking system	-2 cameras -Thermal radiometer -Vis/NIR spectrometer -Dual band (Ka and X) tracking system	-2 cameras -Laser altimeter -2 spectrometers (thermal, NIR) -Accelerometer -Dual band (Ka and X) tracking system
Launch date	May 9, 2012	April 5, 2013	April 22, 2013
Launch vehicle	Orbital Sciences Minotaur IV	Boeing Delta II 7926	Soyuz Fregat
Rendezvous	March 15, 2013	February 17, 2014	January 18, 2014

Foresight

The Foresight mission, proposed by Spaceworks Engineering, uses a small, low-cost ($137.2 million) spacecraft launched on an Orbital Sciences Minotaur IV to rendezvous with, observe, and track Apophis.  Foresight would launch between 2012 and 2014, arriving at Apophis five to ten months after launch.  Foresight would enter into orbit to characterize the asteroid with a multi-spectral imager for one month.  It would then leave orbit and fly in formation with Apophis around the Sun at a range of two kilometers (1.2 miles).  The spacecraft would use laser ranging to the asteroid and radio tracking from Earth over a period of ten months to very accurately determine the orbit and orbit evolution of Apophis in order to assess the probability of a future impact with Earth.
Download the Foresight proposal (PDF format, 1.3 MB) »

Click to enlarge > Foresight mission profile Credit: SpaceWorks / SpaceDev for The Planetary Society's Apophis Mission Design Competition

A-Track

Deimos Space proposed A-Track, a Discovery-class ($387.2 million) spacecraft launched on a Boeing Delta II 7926.  The spacecraft would launch between April 2013 and March 2014 and arrive 10 to 15 months later.  A-Track would rendezvous with and characterize Apophis with a suite of three science instruments including navigation camera, high-resolution multispectral camera, thermal radiometer, and visible and near-infrared spectrometer.  After examining the asteroid's shape, gravity field, and surface composition over a period of five months, A-Track would withdraw to a stable orbit for a six-month tracking period.  Radio tracking of the spacecraft from Earth, combined with modeling of the forces affecting the orbits of asteroid and orbiter, would be used to determine the orbit and orbit evolution of Apophis.
Download the A-Track proposal (PDF format, 1.1 MB) »

Click to enlarge > Mission profile for the A-Track mission Credit: Deimos Space S.L. for The Planetary Society's Apophis Mission Design Competition

APEX

EADS Astrium submitted APEX (the Apophis Explorer), a solar-electric propelled spacecraft that would attempt "the most detailed and extensive investigation of an asteroid ever performed" at a cost of $493.8 million.  APEX would launch on a Soyuz Fregat between April 2012 and February 2015, arriving at Apophis after a cruise lasting 9 to 21 months.  Upon Apophis arrival APEX would study the asteroid's shape, mass, gravity field, rotation state, surface composition and thermal properties using a suite of six science instruments: wide-angle and high-resolution cameras, thermal and near-infrared spectrometers, laser altimeter, and accelerometer.  After initial characterization, APEX would alternate science observations with radio tracking phases over the course of an Apophis year.  A possible extended mission lasting an additional two Apophis years would permit the comparison of Apophis' actual orbital position with the models derived from the first year of observation, validating the results of the nominal mission.
Download the APEX proposal (PDF format, 1.4 MB) »

Click to enlarge > Mission profile for the APEX mission Credit: EADS Astrium for The Planetary Society's Apophis Mission Design Competition

The Planetary Society's Apophis Mission Design Competition: Student Proposals

Although none of the student submissions was judged to be competitive for a prize in the open competition, the review panel was highly impressed with the innovative thinking and creativity demonstrated by a number of the student teams, and selected four for prizes.

Pharos (First prize, student competition)

Pharos was developed by six undergraduate students enrolled in a senior Space Systems Design course at the Georgia Institute of Technology: Jonathan Sharma, Jarret Lafleur, Nilesh Shah, Jillian Apa, Jonathan Townley, and Kreston Barron.  The spacecraft would be a conventionally propelled, Discovery class orbiter with four science instruments (a multi-spectral imager, near-infrared spectrometer, laser rangefinder, and magnetometer) that would rendezvous with and track Apophis.  In addition, it would carry four instrumented probes that would be launched separately, over the course of two weeks.  Accelerometers and temperature sensors on the impactors would measure the seismic effects of successive probe impacts, a creative way to explore the interior structure and dynamics of the asteroid.
Download the Pharos proposal (PDF format, 2.06 MB) »

Oracle (Tie - second prize, student competition)

Oracle, which stands for ORbit determination of Apophis for CLose encounters with Earth, was developed by two final-year undergraduate students in engineering programs at Monash University, Clayton, Australia: Dilani Kahawala and Hemant Chaurasia. The Oracle mission is a small, low-cost, conventionally-propelled spacecraft with only two instruments (a camera and a laser rangefinder), similar to the winning Foresight mission proposal.  However, once the primary survey and tracking missions are complete, the Oracle team proposes to attempt a landing of the spacecraft on the asteroid -- similar to NEAR's landing on Eros.  If the spacecraft survives the landing, the position and rotation of the asteroid could be tracked directly from the spacecraft acting as a beacon on Apophis' surface.
Download the Oracle proposal (PDF format, 400k) »

RA (Tie - second prize, student competition)

RA (Rendezvous Apophis) was developed by the 27 students in the University of Michigan Aerospace Engineering Senior Design class.  RA is another small, conventionally propelled orbiter with camera and laser rangefinder.  In addition to Doppler tracking, the RA proposal team explores the possibility of employing Very Long Baseline Interferometry for tracking the position of the spacecraft.
Download the RA proposal (PDF format, 12 MB) »

Houyi (Honorable Mention, most innovative student proposal)

Houyi was proposed by two graduate students, Peter Weiss of the Hong Kong Polytechnic University and Winnie S. W. Leung of the Hong Kong University of Science and Technology.  Houyi would be a tiny, extremely low-cost spacecraft employing a novel architecture composed of six interconnected CubeSats provided by different suppliers, plus three penetrators equipped with accelerometers and thermal sensors.  It would launch to Apophis by piggybacking on an already-planned planetary launch.
Download the Houyi proposal (PDF format, 1.4 MB) »