The vertical dashed lines give the maximum subsolar temperatures at perihelion for current Itokawa (left) and an assumed extreme orbit (right).
Based on the two bracketing cases of the current orbit and the extreme orbit, it seems at least possible that a near-Earth asteroid like 25143 Itokawa had experienced subsolar temperatures on the order of 650 to 700 K at some locations of its surface.
Another object,, has a similar but less extreme orbit: it has a perihelion of 44.3 AU, an aphelion of 394 AU, and an orbital period of 3,240 years.
Each of the proposed mechanisms for Sedna's extreme orbit would leave a distinct mark on the structure and dynamics of any wider population.
These extreme orbits are believed to be the result of gravitational "scattering" by the gas giants, and the objects continue to be subject to perturbation by the planet Neptune.
And while the shuttle undergoes the kind of stresses that no conventional aircraft endures -- the bone-rattling launching, the extreme cold of orbit and the fiery re-entry -- Mr. Readdy, a former astronaut and pilot, said the high-stress periods were relatively brief for the shuttles, which might fly just dozens of times.
With arrays of such microthruster chips built into its walls, a microsatellite weighing no more than a kilogram could adjust its position in orbit with extreme precision.The attraction of micropropulsion arrays is that they are simple to make and hard to break.
In order to roughly estimate an upper limit of hypothetically attainable temperatures, we assume a quite extreme (but not unrealistic) orbit with a semi-major axis a = 1 (currently a = 1.324) and an eccentricity of e = 0.8 (currently e = 0.28).
Now, a team led by Renu Malhotra, a planetary scientist at the University of Arizona, has examined the orbits of four extreme Kuiper belt objects with the longest-known orbital periods and found an elegant relationship among their orbits: They can be described essentially in simple, whole-number ratios.
These events have been an exceptional opportunity to estimate effects of the thermosphere total density perturbations in extreme conditions on a Low Earth Orbit (LEO orbit corresponding in this study at altitudes ranging from 800 km up to 1400 km).
