Two new Deep Space antennas
 

My company is building a couple of new 34M Deep Space Network antennas for JPL in Australia. The design is based on a couple we've built for them in the past.

They've set up web cams so that progress can be seen real time. So far only one of the foundations has been nearly completed. What you see now doesn't quite capture the scope of what the foundation is really like, We have pictures here in the office of the blasting that was required to create the hole and the construction of the underground building that resides under the top level of the foundation. An ungodly amount of concrete is used.:cool:

The wheel and track antenna will sit directly above the underground facility and utilize beam waveguide.

Some of you guys might find the links interesting.

http://deepspace.jpl.nasa.gov/dsn/images/realtime/latestC1.jpg

http://deepspace.jpl.nasa.gov/dsn/images/realtime/latestC2.jpg

http://deepspace.jpl.nasa.gov/dsn/images/realtime/latestC3.jpg

Very cool.

nice!

stand-alone singular deep space dishes? Or linked with other earth based platforms/dishes for a larger array?.

I'm Curious what frequency, doppler or detectors, radio waves, pulse, or ?

Don't even know if I'm asking the right questions, but still am interested.

Very cool, Michael!

Rusty these are essentially stand alone. The original DSN antennas are pushing 40 plus years now so, these will end up replacing older antennas. They are used for deep space comms and will probably be X Band, not S Band but, don't quote me. We'll likely get the contract for the next two as well.

I've been up to my eyeballs on another program for the Navy since 2005 , so I only pick up bits and pieces on the JPL job. The PM used to be the PM on my program so, I chat with him every once in a while along with the chief Structural Engineer. He's who turned me on to the links. I'm always in his office looking at progress pics. Hopefully my program will have finished up by this coming summer and it'd be a treat to get to go out and participate in the testing of these two. Would be the first beam waveguide type for me. Plus, I love working in OZ.SmileWavy

You should check out the ALMA array. Our group in San Jose designed one of the two antenna types being used. Once we built the first article, proof tested and then received the contract our GM basically gave the program away to one of our sister groups in Texas. They've been building, testing and deploying them in Chile. I think they've recently come on line..:cool:

I hope I'm not asking a dumb question, but what do these do exactly? Radio telescope? (very cool pics btw.)

Communication with manned/unmanned spacecraft

Michael, do you soley do the antennas, or also more of the earth station components?

Hi Jim, We're capable of providing the full systems as well as the antennas. In the past we've gone as far as building the entire station including the civil work such as the Intelsat teleport in Clarksburg, MD. Back in the day we designed and built our own antenna drive systems, RF components, M&C systems....whatever the customer wanted or could think up. Nowadays we source most of the antenna drive systems for our antennas from another sister division in Texas.

We still design full Ground Control Equipment (GCE) systems if the program calls for it.. Broadcast, IOT or TT&C. We're also getting into Troposcatter Radio systems as the market is realizing a need for over the horizon comms at a lower cost than buying SAT BW. We don't really do line of sight.

Whereabouts here are they?

Cool.

Looks like your making a mess ;)

Although these google sat photos look like they were taken a few months ago.

http://forums.pelicanparts.com/uploa...1350880562.jpg

http://forums.pelicanparts.com/uploa...1350880578.jpg

My guess was Tidbinbilla

Here's an article I found
http://www.jpl.nasa.gov/news/news.php?release=2010-429

Yep, just outside Canberra.

I'll see if I can post any other pictures to coincide with the Google Map pic. That pic was taken while the foundations for the right hand pad were being poured.

We do radio telescope as well Scott. We built the first Keck dome and drive system, optics positioning but, not the optics themselves. We also built the South Pole Telescope. The Alma antennas are really smaller radio telescopes making up a large array.

Finally have something worth looking at. Structure going up. Enjoy!

The reflector lift looks to be about a week or two out..

Starting to look like a real antenna.

http://forums.pelicanparts.com/uploa...1367511284.jpg

can you tell us more about the materials used in sats. aloft as well as ground based antennas?

seems like even on the ground you'd want something stiff and light wt. ...

Well, can't tell you much about the birds other than weight is critical for the payload obviously. In orbit, additional weight means additional fuel for manuevers which in the end determines the maximum life of the bird.

I'm a ground guy.... Stiffness required in the antenna is a function of the frequency and how much deformation you can tolerate. It's all about maintaining the reflector/subreflector Geometry (focusing).

All of my group's antennas are high performance and are all steel structure with thin skin Alu reflector panels. Sometimes our sub reflectors are alu., most are FG. We have sister divisions that build higher volume, lower performance antennas with alu. back up structures mounted on Galv kingposts. We try to keep weight down as much as is reasonable (keeps motor sizing down) but, in the end all the weight and stiffness is determined by the need to keep that reflector RMS down as much as we can throughout all environmental effects. Surviving 150mph winds requires a little weight as well.;)

On our ALMA antennas, the reflector panels are milled out of billet Alu to maintain their stiffness which results in a very heavy antenna for it's relatively small size.

thx - how much does movement of any element degrade the reception/transmission?

It's a function of frequency and the size of the reflector diameter. The larger the diameter, the more antenna signal gain yet, also results in a smaller signal beamwidth.

The RMS value of the reflector is determined by measuring many different points on all of the individual panels to determine how far off we are from the theoretical curve. The theoretical curve is designed to take all signal (out of phase at all points to any other point) and focus the signal by combining phase. That is how the overall power (Gain) is affected in both transmit and receive. Any deviation from the theoretical means a portion of signal is not combined (lost) and Gain goes down. It's a trade off between Transmit and Receive as we have to maintain frequency separation.

The smaller the beamwith (function os diameter and frequency) determines how accurate our pointing must be. Again, stiffness in the structure helps this.

Let's put it this way.. On a program I'm working on (can't give specifics).... 1/100th of a degree of pointing is the difference between being on the peak of the beam.... or not. Typically on the order of -20dB or greater.

This, at at target 22k miles away.

Forgot to mention that the reflector support is designed to minimize the transmission of steel deflection in the Back Up Structure (BUS) to the reflector mounting points due to thermal (solar).

The DSN is unique asset for planetary exploration. In recent years, some of the deep space missions have needed to work around ground station operational issues. As an interplanetary spacecraft developer I'm thrilled to see the US investing in infrastructure upgrades.

The 34M BWG antennas will support relatively high bandwidth data downlink from Mars, meaning roughly 110kb/sec with a 15W solid state transponder at Mars, D/L freq ~8.4GHz. Traveling Wave Tube Amplifiers (TWTAs) that deliver ~ 100W of RF power will support ~ 1Mb/s downlink. Each spacecraft has a unque frequency assignment so the DSN can support comm links with multiple assets at Mars. The US currently has 2 operational orbiters and 2 operational rovers on the surface. Next orbiter launches Nov 18th 2013, next lander launches March 2016.

Love the DSN, it's a discriminator for the US solar system exploration effort!!!

That gets me hot......:D