Posts Tagged ‘Air Force Space Command’

When Air Force Space Command’s Commander, General Willie Shelton testified to the Senate that LightSquared’s high-powered telecommunications signal would degrade, disrupt, and deny the GPS signal, there was plenty of disagreement.  Much of the disagreement was from LightSquared who had plowed plenty of investor money—about a billion dollars so far—into the effort and had lots to lose.

So now, the study is done and the finding confirms Shelton’s concern: LightSquared’s terrestrial signal will degrade, disrupt, and deny the GPS signal.  For LightSquared, it’s all over but the crying.

LightSquared started out with a largely space-based (and low-powered) scheme, but went more terrestrial for cost and performance reasons.  The fact their signal was adjacent to the GPS signal was…let’s just say that part of the architecture was not well thought through.  How so?

…aviation users could effectively experience a blackout of GPS capabilities, particularly around densely populated areas, where LightSquared ground stations are expected to be spaced 400 to 800 meters apart (snip)

At altitudes of 3,040 meters and below, aircraft could not rely on GPS for navigation over the nation’s capitol, most of Virginia and Maryland, and significant parts of Pennsylvania and New Jersey (snip)

…police cars could not acquire GPS signals within 182 meters of a LightSquared tower broadcasting at the maximum allowed power of 15 kilowatts (snip)

Signals to ambulances and fire trucks were nullified within 304 meters of a tower.

And now for the LightSquared crying part:

There are no feasible options for mitigating LightSquared interference…outfitting all GPS aviation receivers with special filters to ensure they do not pick up LightSquared signals would take between seven and 15 years and cost an unknown but extremely large sum…[also], the filters would reduce receiver performance. (snip)

…modifying LightSquare antenna patterns and exclusion zones or operating at lower power levels, are not good solutions because they would require more ground stations to be deployed, increasing the aggregate power output (snip)

The only remaining viable solution… [is] for LightSquared to acquire the rights to another part of the electromagnetic spectrum.

Who will rule the day here, GPS or LightSquared’s billion dollar baby?  Well, consider this:

According to the GPS Industry Council, a trade group, GPS represents a $22 billion investment by the federal government and billions of dollars more by end users to develop applications that serve defense, public safety and homeland security needs, as well as a range of industries.

So who’s the villain here?  LightSquared, who had to know GPS interference would be an issue?  The FCC who licensed the effort?  Or is it GPS, which has become all things to all peoples at all times, resulting in a perhaps dangerous dependency on its space-based signal?

GPS has its own set of problems but getting government and industry unaddicted to it can’t be blamed on its inherent usefulness.  Over to you, FCC and LightSquared…


Do you want to know–in part–why space is so expensive?  It’s because time is money.

In the example we’re discussing here, it means the pending anomaly resolution for the AEHF-1 mission will (not just might) drive the AEHF-2 launch to slip by a year.

I’m not sure what the cost to keep the AEHF-2 team together another year (for now) is, but I’m confident it’s something greater than zero.

Back in August, AEHF-1’s liquid apogee engine did not fire as expected resulting in a rescue plan to eventually put the spacecraft in its proper orbit.  The good news is it looks like AEHF-1 will eventually get where it needs to go.  The bad news is that it will likely approach a year to do so.

Regarding the anomaly, SpaceFlight Now reports the issue is thought to be something other than the IHI Aerospace liquid apogee engine, even as the engine itself did not fire as required.

“We are not expecting any major redesigns to Vehicles 2 or 3 associated with this issue,” Madden said. “I think it’s going to be more (like) some tests and visual inspections that we have to do.”

Madden works AEFH on behalf of Air Force Space Command’s Space and Missile Systems Center.  When he says the AEHF team isn’t expecting any major redesigns, that certainly leaves open non-major redesign work.

Bloomberg reports AEHF-1 will be at least four months late to reach its proper orbit.  The Air Force Association’s Daily Report says AEHF-1 will likely be roughly seven months late.

Spaceflight News quotes a Space and Missile Systems Center authority as saying seven to nine months late.

Sounds like AEHF will be late in reaching its final orbit, eh?

What was the problem?  The liquid apogee engine.  There are several vendors and versions of such engines, so it remains unclear who’ll get the blame on this.

While the liquid apogee engine (LAE) is sometimes described as a “100-pound engine” it is almost certainly a 10-pound engine that makes 100-pounds of thrust.  Regardless, the LAE did not do its job.

The workarounds will still allow for AEHF’s expected 14-year operational life cycle, it will just start months later than envisioned.

I’m thinking the liquid apogee engine will have a pretty serious engineering review before it flies again.

AEHF-1 Encapsulation

AEHF-1 is proceeding nominally to fly on an Atlas V on Saturday, 14 Aug from Cape Canaveral Air Force Station, Florida.  The launch window is two hours, 0707 to 0907.

AEHF is an Air Force operated, highly-capable, commercially-based spacecraft with ten times the comm throughput of Milstar, although that’s not completely an apples to apples comparison.  As you can see from the photo, it’s plus-sized at 13600 pounds and needs a five-meter diameter fairing.

United Launch Alliance has a tremendous piece of explanatory literature addressing the satellite, the booster, the upper stage, launch facilities, and the launch profile at this site.

Go Atlas, go Centaur, go AEHF-1!

The New York Times article on the X-37 contains two very weak assertions.

How about this one: “The craft’s payload bay is the size of a pickup truck bed, suggesting that it can not only expose experiments to the void of outer space but also deploy and retrieve small satellites.”  (emphasis added)

I guess you could assert that the shuttle has ‘retrieved’ a satellite regarding the repair missions with the Hubble.  I also suppose you could assert the X-37 could do such a mission as a space debris mitigation effort–a demonstration possibly–but even if it had the energy to maneuver to a spacecraft to retrieve it, how would it get it in the cargo bay?  How would the payload be secured for a return trip to earth, including an airplane-like landing?

The second assertion is the space weaponization thing.  It seems kind of analogous to when people have to explain that they are actually politically correct when accused of a PC-type crime.  Accordingly, the X-37 is associated with the phrase ‘space weaponization’ several times and it is denied several times.  The Times Online article Launch of secret US space ship masks even more secret launch of new weapon is m-u-c-h more ominous.  I’m all for conspiracy theories, but come on…

Really, the idea the X-37 is a space weapon is beyond the pale. First level questions like what weapon(s) does it carry?; what would be its target(s)?; how would the weapon(s) be delivered to the target(s)?, are ignored.

Regarding an X-37 payload, in the past the concept of ‘on-orbit spares’ has come up, but the idea was never compelling.  After all, if you’re going to put something on orbit, it is probably a very capable system and you probably want to use it right away.  As such, you’d be expected to turn the satellite on as soon as you can.

A vehicle like the X-37 could preserve a capability to deploy ‘sleeping’ contingency satellite(s) for an extended period of time.  If there was war here on earth that needed the kind of space capabilities the X-37’s payload could provide, then it could deploy the satellites almost immediately.  Conversely, if they didn’t need to be deployed, the X-37 could be brought back with the payload intact for use on a subsequent mission.  Or they could be deployed just prior to the X-37’s de-orbit to add space capability.

Taking off and landing with the same payload–on a first mission–makes little sense.  The X-37 first needs to show it can deploy a payload after some period of on-orbit storage.  By the way, a payload that could fit into a pickup truck’s bed seems pretty likely to not have new sensors on it.  You would  really expect this would be about employing relatively mature technologies in new ways.

Groan.  Wasn’t the shuttle a reusable booster?  Didn’t EELV promise cost savings?

Here’s the link to the Aviation Week article…

When I read about savings of over 50%, I think about EELV and the cost savings it was asserted to create.  EELV was a massive ‘cost avoidance’ program, that is, by creating and using new families of launch vehicles, the USAF could get away from brutally expensive ‘heritage’ systems like the Titan IV.

Of course, the savings–the cost avoidance–never materialized.  Paper rockets are cheap and things cost more and more as they move further away from Powerpoint.

EELV’s cost problem was rooted in the bogus assumption there would be lots of EELV launches and ergo, plenty of cost sharing and a low per-unit expense. These were, of course, all wrong.  Its advocates didn’t see that foreign launch competitors, with advantageous labor rates, subsidization, and greatly reduced regulatory entanglements, would end up as the  way for commercial users to go.

Give the SpaceX and Microcosms of the world a chance to compete.  Reusable if it makes sense, expendable if it doesn’t.

New Scientist reports that astronomers are concerned about restrictions on the use of lasers.  Astronomers use lasers to focus their telescopes. 

The lasers, which are needed to adjust the adaptive optics of the telescopes, also appear to be capable of disrupting certain satellite sensors.

Air Force Space Command has “restricted when and where US observatories can fire them, and the observatories have voluntarily complied, with little impact on astronomy.”

However, restrictions which started about two years ago may now be more burdensome, increasing from a few blackout periods per night to hundreds.

Astronomers don’t really know what the risk to the spacecraft is.

While the U.S. Air Force takes the heat in the article (and the comments, many of which are quite comical), it is likely Space Command is only the messenger here.  Consider a few of the comments (in paraphrase), with rejoinder:

  • So what of the satellites from other nations, EU, Russia, China etc? They don’t matter?
    • Of course they matter, but the USAF doesn’t control those nations’ communications on this topic with the U.S. observatories
  • If the Air Force feels the need to spy on mountain tops…they should do so at their own risk
    • The Air Force doesn’t fly spy satellites; those belong to the intel community.  Anyway, the U.S. mountain tops are already pretty well understood.
  • Iran can stop worrying and just build thousands of vertically aimed lasers.  They can build what they like then
    • As one commenter points out, a satellite attack can be considered an attack on U.S. sovereignty
  • The government is messed up if it is more important to monitor the globe than to look into the universe
    • Well, that’s your opinion

Have a great day!