Into Space

This weekend was an auspicious one as regards travel into space.

First off, the first privately funded and developed vehicle sent into space.

SpaceX is a privately funded company. Wired Science covers the story:

SpaceX has made history. Its privately developed rocket has made it into space.

After three failed launches, the company founded by Elon Musk worked all of the bugs out of their Falcon 1 launch vehicles.

The entire spectacle was broadcast live from Kwajalein Atoll in the South Pacific. Cameras mounted on the spacecraft showed our planet shrinking in the distance and the empty first stage engine falling back to Earth.

As the rocket ascended, cheers rang out during every crucial step of the launch sequence, and at the final stage their headquarters in Hawthorne, California erupted in excitement. (Wired.com viewed the launch over the Internet on SpaceX’s live webcast.)

The tensest moment came just before stage separation. At that critical juncture, the third launch attempt had failed. This time, it worked out perfectly.

Eight minutes after leaving the ground, Falcon 1 reached a speed of 5200 meters per second and passed above the International Space Station.

Earlier in the week, China put more astronauts into space (they’re only the third country to put a person into space independently, after the Russians and Americans). But for a first, they sent one of them on a spacewalk. From CNN:

A Chinese astronaut has completed his country’s first-ever spacewalk as part of an ambitious program that is starting to rival the United States and Russia in its rapid expansion.

Mission commander Zhai Zhigang waves Chinese flag after emerging from his spaceship.

State broadcaster CCTV showed live images of Zhigang as he floated out of the orbiter module’s hatch. “Greetings to all the people of the nation and all the people of the world,”

Zhai Zhigang waved to an external camera as he emerged from the hatch of the Shenzhou-7 spaceship on Saturday.

He later held a small Chinese flag, waving it in space.

Zhai returned to the interior of his capsule and closed the hatch after less than 20 minutes outside.

Video of the EVA (extra vehicular activity – geekspeak for “spacewalk”) can be found at the click. National Geographic has the story, and some nice video as well.

So lots of space. News.

How fast

In response to a very good question ™ posed by one of my students, a response. First, the question:

Question

How fast do spaceships or probes or satellites go? How long would it take for them to reach the closest star? The center of the galaxy?

Answer

The Voyager space probes, launched in the late 1970s, went to visit Jupiter and would eventually travel outside of our solar system. It’s actually approaching the Oort Cloud, and the true boundary of the system, called the Heliopause.

Voyager is travelling at about 56 000 km/h [1]. A different source cites a maximum velocity of 62 856 km/h [2]. It’s hard, sometimes, to decipher all of the conflicting information. At any rate, it will reach Proxima Centauri in about 19 000 years. Yawn.

More recently, the New Horizons space probe left Earth at a speed of 58 016 km/h, which is also quite impressive. [3] After passing close by Jupiter, and using something called gravity assist, it was accelerated to a speed of 83,700 km/h. [4] Even more impressive.

However, that’s not the whole story. (Neither is this example, as you will soon see.) The Pioneer 10 probe, sent out in 1972, was also accelerated by Jupiter. It reached a speed of 173 000 km/h. Faster yet.[5]

But there is… another. Launched in the mid 1970s by Germany (and the US), Helios was sent to orbit the Sun. Being accelerated by a mass that’s ten times that of Jupiter means a bit of a boost. Up to 240 000 km/h [6] (wikipedia says 252,792 km/h, but with no sources).

That seems to be the record. And it would take about 4 500 years for it to reach Proxima Centauri. If it were pointed towards there, that is.

Even better

Even better than the last post, this one. It puts the Phoenix and parachute image in a bit of context. In this case, Heimdall Crater

To understand what’s going on, look at the box at the bottom left. It’s the magnified portion from the middle left part of the crater. On the larger photo, all you see is a speck of white, but that’s Phoenix

Click on the image to see it in full resolution.

It looks like Phoenix is headed for Heimdall, but really, it’s 20 km in front (towards the camera) of it. For a sense of scale, Hiemdall itself is ten km across, and the lander is 12 km above the surface. It just looks like it’s falling into the crater.

A little thing called parallax.