Low budget space vehicle tracking

So, assuming that we can build an orbital vehicle, get a launch permit,
etc - what is the best (or cheapest) method of tracking the vehicle
after launch?

Specifically, what methods are available for continuous telemetry for a
private launch? Would you have to set up listening posts around the
globe? Can you use an existing network?

Another related question - is it possible to get telemetry during
re-entry? (Assuming a very high altitude / high L/D / high Drag to
mass re-entry) I know that the shuttle manages to get some data
through its plasma sheat, so is that technology something a small
company can use?

Thanks!

-David

David Summers wrote:
So, assuming that we can build an orbital vehicle, get a launch permit,
etc - what is the best (or cheapest) method of tracking the vehicle
after launch?

Well, there is best, and there is cheapest.
Best is multiple radar stations, doing skin-track.

Cheapest is probably omnidirectional 802.11 on the launcher,
and a big antenna on the ground, and GPS, and a couple of stations
downrange.
You talk to the launcher until it goes over the horizon, with it informing
you of its track.
(and you verify it somewhat by verifying where the antenna is pointed.)

Then, you pick it up at the second station, when it's in orbit.

A moderate strobe on the spacecraft, timed to go off at the GPS second,
where it's closest to one of several observation points may work, and
be fairly pointing tollerant.


Specifically, what methods are available for continuous telemetry for a
private launch? Would you have to set up listening posts around the
globe? Can you use an existing network?

Another related question - is it possible to get telemetry during
re-entry? (Assuming a very high altitude / high L/D / high Drag to
mass re-entry) I know that the shuttle manages to get some data
through its plasma sheat, so is that technology something a small
company can use?

You need a relay satellite of some sort, to talk out the back of the
plasma sheath.
Some of the video broadcast satellites may work.

If Iridium recievers work at high delta-vee, they can solve a lot of
these problems.

On 2005-02-15, David Summers wrote:

Another related question - is it possible to get telemetry during
re-entry? (Assuming a very high altitude / high L/D / high Drag to
mass re-entry) I know that the shuttle manages to get some data
through its plasma sheat, so is that technology something a small
company can use?

The Shuttle's telemetry, as I understand it, doesn't go "through" the
plasma sheath, but rather out of the "back" of it, and is relayed
through one of the TDRS satellites in geostationary orbit.

It may well be considered impractical to replicate this capability
yourself.

--
-Andrew Gray

David Summers wrote:
[...]
Specifically, what methods are available for continuous telemetry for a
private launch? Would you have to set up listening posts around the
globe? Can you use an existing network?

Well, for locating your vehicle, you can use GPS. It gets really hairy above
a hundred kilometres or so, but it's still usable with some very custom
software. A few years ago someone did some tests with a satellite in LEO. I
believe that it's event usable by vehicles *above* the GPS satellite
network, if you know what you're doing.

For getting the information back to the ground --- could you use a satellite
phone? Lousy bandwidth, they max out at 9600bps, but the network's in place
and is reliable. However, you might end up with problems due to altitude
and doppler shifting meaning that the satellites can't hear you any more.

Another related question - is it possible to get telemetry during
re-entry? (Assuming a very high altitude / high L/D / high Drag to
mass re-entry) I know that the shuttle manages to get some data
through its plasma sheat, so is that technology something a small
company can use?

I believe the shuttle relays telemetry through satellites during reentry;
the plasma sheath only covers the lower portion of the vehicle, so it can
still transmit upwards (with difficulty). I have no idea what satellites it
relays off.

--
+- David Given --McQ-+ "Apatheism: the school of belief where on doesn't
| | particularly care if there is/are god(s)." ---
| ) | Capt. Gym Z. Quirk
+- www.cowlark.com --+

I believe the shuttle relays telemetry through satellites during reentry;
the plasma sheath only covers the lower portion of the vehicle, so it can
still transmit upwards (with difficulty). I have no idea what satellites it
relays off.

TDRS. When data first dropped out from Columbia, this wasn't totally
unexpected, in particular because it was at that point in time at an
attitude where the tail was getting in the way.

Jan

On 15 Feb 2005 10:14:33 -0800
"David Summers" wrote:

So, assuming that we can build an orbital vehicle, get a launch
permit, etc - what is the best (or cheapest) method of tracking the
vehicle after launch?

I googled around for a bit and it seems that amateur radio satellites
are still in orbit and in use.

See: http://www.qsl.net/w8dro/

There appear to be many spacecraft available. The only question is
whether you can relay through them from a high altitude.

For positioning GPS may be the go, as others have suggested. You could
look at using VHF localisers, still in use for aviation around the
world.
--
Michael Smith
Network Applications
www.netapps.com.au | +61 (0) 416 062 898
Web Hosting | Internet Services

David Summers wrote:
So, assuming that we can build an orbital vehicle, get a launch
permit,
etc - what is the best (or cheapest) method of tracking the vehicle
after launch?

....snip....

Unless the government requires close and continuous tracking,
I fail to see the urgency. When I learned to fly a little
over six decades ago, the pilot navigated and told anyone
interested on the ground the aircraft's position. Perhaps
satcom and GPS can be adapted to orbital altitudes to augment
on-board inertial systems and other means--which would give
superb positioning information.

Failing info from GPS, etc., you are above the weather for
star fixes. Celestial nav should be a snap with modern
computers, as compared to the WWII laborious hand calculations.
With a winged space transport, rather crude positioning should
be adequate to get to a good subsonic initial position--where
normal aircraft nav aids and landing systems should work fine.
I really don't see the problem--unless someone insists on
making a problem out of a quite manageable situation.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

-David

I believe that something like these off the shelf Telemetry radios
would work, http://www.maxstream.net/products/xt...ule/9xtend.php
I have reports of the 100mw units working to over 60 miles.
They would probably need to be modified to handle the doppler unless
you only wanted to communicate when directly overhead.

You would probably need a significant antenna....
Something like the Radio Ham EME setups...
http://www.nitehawk.com/rasmit/gallery.html

If you choose a band that had lots of EME activity the Hams would
liekly be very very helpful in providingh trackign and communication
services.


Paul

Len wrote:
David Summers wrote:
So, assuming that we can build an orbital vehicle, get a launch
permit,
etc - what is the best (or cheapest) method of tracking the vehicle
after launch?

...snip....

Unless the government requires close and continuous tracking,
I fail to see the urgency. When I learned to fly a little

It's very nice to have more-or-less continuous tracking and data relay
if you are not sure of the device, or even if you are, and things go
wrong.

over six decades ago, the pilot navigated and told anyone
interested on the ground the aircraft's position. Perhaps

If you've got a pilot onboard, some of the problems go away (as long
as the pilot can communicate the problem to the ground in some manner),
but for stuff like finding out on orbit that somebody put in the
solar array extend motor in backwards, and you need to try reversing it
before the batteries run out, rapid comms is pretty much essential.

On 2005-02-17, Peter Fairbrother wrote:
Andrew Gray wrote:

On 2005-02-15, David Summers wrote:

Another related question - is it possible to get telemetry during
re-entry? (Assuming a very high altitude / high L/D / high Drag to
mass re-entry) I know that the shuttle manages to get some data
through its plasma sheat, so is that technology something a small
company can use?

The Shuttle's telemetry, as I understand it, doesn't go "through" the
plasma sheath, but rather out of the "back" of it, and is relayed
through one of the TDRS satellites in geostationary orbit.

It may well be considered impractical to replicate this capability
yourself.

Hmmm ... plasma is conductive ... would a plasma sheath make a good
antenna?

I doubt it.

Incidentally, a recent post on sci.space.history mentioned a couple of
Gemini research papers, which involved injecting water into the plasma
sheath during re-entry -

FLIGHT INVESTIGATION AND ANALYSIS OF ALLEVIATION
OF COMMUNICATIONS BLACKOUT BY WATER
INJECTION DURING GEMINI 3 REENTRY
By Lyle C. Schroeder and Francis P. Russo
Langley Research Center

A method of overcoming reentry communications blackout by injecting
water into the flow field was demonstrated during the Gemini-Titan 3
(GT-3) mission. Significant levels of signal strength increase during
the early portion of the water injection sequence over an altitude range
from 272000 to 246000 ft (82.90 to 74.98 km) were noted by ground
stations on VHF telemetry (230.4 MHz) and VHF voice (296.8 MHz).
Enhancement of C-band beacon signal (5690 MHz) was observed during the
latter portion of the water injection sequence over an altitude range
from 200000 to 160000 ft (60.96 to 48.77 km).

[NASA TM-X-1521, March 1968]

Not sure if any more research was done on this, though.


--
-Andrew Gray