from the freight-train-hopping-IN-SPAAAAAACE! dept.
Traveling around space can be hard and require a lot of fuel, which is part of the reason NASA has a spacecraft concept that would hitch a free ride on one of the many comets and asteroids speeding around our solar system at 22,000 miles per hour (on the slow end). Comet Hitchhiker, developed at NASA's Jet Propulsion Laboratory, would feature a reusable tether system to replace the need for propellant for entering orbit and landing on objects.
The spacecraft would first cast an extendable tether toward the object and attach itself using a harpoon attached to the tether. Next, it would reel out the tether while applying a brake that harvests energy while the spacecraft accelerates. This allows Comet Hitchhiker to accelerate and slowly match the speed of its ride, and keeping that slight tension on the line harvests energy that is stored on-board for later use, reeling itself down to the surface of the comet or asteroid. A comet hitchhiker spacecraft can obtain up to ~10 km/s of delta-V by using a carbon nanotube (CNT) tether, reaching the current orbital distance of Pluto (32.6 AU) in just 5.6 years.
Unfortunately rocket scientists apparently don't read SN, or they'd know from discussions last year that it simply won't work. It seems that the idea defies "basic orbital mechanics" and "makes no sense".
Scientists have found that the surface of comet 67P/Churyumov-Gerasimenko—the target of study for the European Space Agency's Rosetta mission—can be divided into several regions, each characterized by different classes of features. High-resolution images of the comet reveal a unique, multifaceted world.
ESA's Rosetta spacecraft arrived at its destination about a month ago and is currently accompanying the comet as it progresses on its route toward the inner solar system. Scientists have analyzed images of the comet's surface taken by OSIRIS, Rosetta's scientific imaging system, and defined several different regions, each of which has a distinctive physical appearance. This analysis provides the basis for a detailed scientific description of 67P's surface. A map showing the comet's various regions is available at: http://go.nasa.gov/1pU26L2
The new comet maps will offer valuable insights for members of the Rosetta team, who are gathering in Toulouse, France, on September 13 and 14, to determine a primary and backup landing site from five candidates they previously had selected.
For background, see: Rosetta: Landing Site Search Narrows which was published on August 25, 2014:
The European Space Agency's Rosetta mission has chosen five candidate landing sites on comet 67P/Churyumov-Gerasimenko for its Philae lander. Philae's descent to the comet's nucleus, scheduled for this November, will be the first such landing ever attempted. Rosetta is an international mission spearheaded by the European Space Agency with support and instruments provided by NASA.
Choosing the right landing site is a complex process. It must balance the technical needs of the orbiter and lander during all phases of the separation, descent and landing, and during operations on the surface, with the scientific requirements of the 10 instruments on board Philae. A key issue is that uncertainties in navigating the orbiter close to the comet mean that it is possible to specify any given landing zone only in terms of an ellipse—covering about-four-tenths of a square mile (one square kilometer)—within which Philae might land.