Mike’s Tweets

How to Deorbit a Spacecraft

The recent uncontrolled reentry of the UARS spacecraft got a lot of attention last week as NASA and the JSpOC tried to track the vehicle as it reentered.

It doesn’t have to be done this way, however. On March 13, 2011, a commercial spacecraft was purposefully reentered into the Pacific ocean 3000 miles southeast of […]

How Reentering Spacecraft Are Tracked: NASA vs. JSpOC

On a previous post I mentioned that contrary to what a lot of the recent news reports imply, NASA itself is not in the business of tracking uncooperative or (in the case of UARS) dead spacecraft. NASA normally will determine a satellite’s orbit (called “Orbit Determination”) via communications with the spacecraft. Both ranging (measuring the […]

Finding Snoopy

As you may have seen on the web in the last few weeks, the search is on to locate Snoopy, or the ascent stage of the Apollo 10 Lunar Module:

Discovery.Com Universe Today Skymania CollectSpace

I am helping Nick Howes and his students in the UK (and elsewhere) to try and locate Snoopy, the […]

Final Word on UARS Impact?

After the previous post, I had contacts from several twitter followers with suggestions for improving my predictions. In particular @Marco_Langbroek suggested that 120 km (rather than 80 or 75 km) was the magic number for atmospheric contact, and he further suggested that the 4:16 UTC time originated with the the Joint Space Operations Center (www.space-track.org). […]

UARS Sighting near Portland?

A twitter friend @musicscott emailed me a picture he had taken Friday night of a region of the sky near Ursa Minor. In his picture he had a streak that he thought may have been a piece of the UARS satellite.

Streak near Ursa Minor provided by @musicscott

He provided me with the original […]

Taking a Guess at Where UARS Came in

I’ve seen lots of hocus-pocus out there on where the UARS spacecraft re-entered. Lots of bogus videos are out along with vague descriptions of where the spacecraft landed (some that narrow it down to the Pacific Ocean). While NASA’s taking their time giving us an impact point, they are giving us enough information to calculate […]

Anatomy of a Near Miss

I wanted to revisit the previous post, describing a near miss of ISS I witnessed back in August. Recall that both my brother and I saw the same 2 satellites cross in the sky at the same time.

First, let’s just take a look at the geometry that allows satellites to be seen in the […]