Parade of Planets

Last week we saw sunrise from the surface of Mars. Martian days (Sols) are 24 hours, 39 minutes long. 7 Sols later it is 8:36 AM July 8 UT on Earth, sunrise at Gusev Crater. Because of the 12-minute time delay, the image will appear 10:48 PM July 7 Hawaii time. Earth is just past her maximum angular separation from the Sun, and will soon be circling behind. Below Earth is Jupiter, fortuitously in position to be seen behind the inner planets. The new morning star below Jupiter is Venus. Mercury is on the other side of the Sun, visible every day at sunset. From the vantage point of Mars one can easily observe the inner worlds orbit the Sun.

This is Mars from 1.4 million km, the view from a human spacecraft 6 Sols from landing. Even 6 days out, Mars is 4 times the distance from Earth to the Moon. ARES was launched from Kennedy Space Center October 28, last day of the 2009 Mars launch window. This ARES, accelerating to Earth escape velocity, has been on a Hohmann transfer orbit to rendezvous with Mars on July 13, 2010. As the spacecraft is near aphelion in her elliptical path, Mars appears astern approaching at 2.65 km/sec. Apollo astronauts also saw the Moon overtake them from behind.

Even one day from landing Mars will be 235,000 km away, 2/3 the Earth-Moon distance. On that exciting day the crew will see the planet grow from a tiny disk to dominate the sky. ARES would have used all her cryogenic fuel escaping Earth, and must aerobrake to enter Mars' atmosphere. She will encounter Mars' atmosphere on the side facing the Sun, gaining about 300 m/sec from the planet's rotation. NASA technicians have launched 7 spacecraft to land on Mars in this manner, with only one failure. This ARES mission would have a good chance of success.

Once on Mars, the adventure would be just beginning. A resupply mission can not land until the next launch opportunity 26 months in the future. Lacking sufficient water and oxygen, the crew would have to find water on Mars. The possible scientific gains would make this risk more than worthwhile. The crew on Mars would every morning enjoy a view like this parade of planets.

Habitation Intention kindly hosts an "awe-inspiring" Carnival of Space!