2017-12-20 12:06:03
NASA Is Picking Finalists for a Space Mission. Here Are Its Options.

12:06, December 20 477 0

Venus? Saturn or one of its moons? A giant crater near the south pole of the moon?

Those are some of the destinations NASA is considering in a competition it calls New Frontiers for a forthcoming robotic planetary mission. It is like the interplanetary version of “Shark Tank.”

The space agency will announce the finalists on Wednesday. (The previous New Frontiers competitions featured two or three finalists.) Each selected team will get $4 million to flesh out its idea, and NASA will decide in 2019 which mission to actually build and launch by the end of 2025.

NASA flies two types of science missions. For some like the Mars Curiosity rover and upcoming spacecraft that will explore Jupiter’s moon Europa, the agency decides where it wants to go and then builds and operates the mission itself.

For others, including New Frontiers missions, NASA solicits suggestions from inside and outside the space agency.

NASA has flown three New Frontiers missions. The first, New Horizons, zipped past Pluto two years ago. The second is Juno, currently looping around Jupiter, and the third, Osiris-Rex, is en route to an asteroid.

For this round of New Frontiers, the agency will spend up to $850 million for the spacecraft, instruments and mission operations. Add in the cost of the rocket to get the spacecraft off the ground, and the total price tag will be about $1 billion.

NASA received 12 proposals but released no information about them. The teams, however, are free to discuss their ideas publicly.

Here is what we know about them.

In some ways, Venus is a closer twin of Earth than Mars is (it is much closer in size), and scientists wonder how a planet that probably started with temperate conditions turned hellish. While NASA has sent a flotilla of spacecraft to Mars, it has not been to Venus since the end of the Magellan mission more than 20 years ago. Three groups have proposed missions to return to the solar system’s second planet.

Venus In Situ Atmospheric and Geochemical Explorer, or Visage, led by Larry W. Esposito of the University of Colorado, would put a lander on Venus, drilling into the rocks and taking pictures. In the inhospitable environment — temperatures of hundreds of degrees and clouds of sulfuric acid — Visage would survive for only a few hours.

Venus In Situ Composition Investigations, or Vici, led by Lori S. Glaze of NASA’s Goddard Space Flight Center, would put two landers on Venus, with similar goals to the Visage probe.

The Venus Origins Explorer, or Vox, would explore Venus with an orbiter and an atmospheric probe. Unlike the other two proposals, Vox, led by Suzanne E. Smrekar of NASA’s Jet Propulsion Laboratory, would not directly sample the surface, but would instead provide global study of the planet’s mineralogy and search for signs of volcanism.

The South Pole-Aitken Basin on the moon has long been on the wish list of destinations for planetary scientists. The basin, 1,600 miles wide and eight miles deep, is the scar of a cataclysmic impact more than 4 billion years ago, deep enough that parts of the moon’s mantle could have been exposed.

Therefore a spacecraft going there would be able to pick up bits from the inside of a rocky world not easily found elsewhere in the solar system. The proposed MoonRise mission would even bring some dirt and rocks back to Earth for scientists to examine directly.

The European Space Agency’s Rosetta mission spent a couple of years flying around Comet 67P/Churyumov-Gerasimenko, even putting a small lander down on the surface.

Comet Nucleus Dust and Organics Return, or Condor, proposed by NASA’s Jet Propulsion Laboratory, would return to Comet 67P, scoop up samples and bring them to Earth for closer study.

The Comet Rendezvous, Sample Acquisition, Investigation, and Return, or Corsair, a collaboration between NASA Ames Research Center and the Johns Hopkins University Applied Physics Laboratory, is similar to Condor except it would bring back samples from a different comet: 88P/Howell.

Van Kane, a blogger following planetary science missions, reported in October that there is a third proposal for a cometary sample return, named Caesar, led by Steven W. Squyres of Cornell University, the principal investigator for the Opportunity rover on Mars. But nothing else is known, not even what Caesar stands for.

To build upon the success and legacy of the Cassini mission to Saturn, which ended this year, five missions have been proposed to return to the ringed planet or its moons.

The Saturn Probe Interior and Atmosphere Explorer, or Sprite, would do essentially what the Cassini spacecraft did in September — drop into Saturn — except Sprite would go much deeper. Measuring the ratio of helium to hydrogen would explain where Saturn formed, an important piece of information for understanding how the solar system came together.

Enceladus, a tiny moon of Saturn, shoots a plume of ice from its south pole, emanating from a subsurface ocean. The Enceladus Life Finder, or Elf, led by Jonathan I. Lunine of Cornell University, would fly through the plumes with instruments that could identify carbon-based molecules and other ingredients to discern if the oceans possess conditions amenable for life.

Another proposal to visit the icy satellite, led by Christopher P. McKay, an astrobiologist at NASA Ames Research Center, is called Enceladus Life Signatures and Habitability, or Elsah, but no details are known.

Two missions have also been proposed to study Titan, which is Saturn’s biggest moon and has seas of hydrocarbons.

Oceanus, led by Christophe Sotin, the chief scientist for solar system exploration at the Jet Propulsion Laboratory, would study Titan from orbit.

Dragonfly, proposed by the Johns Hopkins University Applied Physics Laboratory, is perhaps the most unusual spacecraft concept. It would essentially send a self-flying helicopter to explore Titan, hopping from one intriguing spot to another.