Start of the True Space Age

[LongTomH]

Last edited Thu May 29, 2014, 02:09 PM - Edit history (1)

by Adam Crowl
source: Icarus Interstellar
May 7 2014

http://www.icarusinterstellar.org/start-of-the-true-space-age/

Watching the recent soft splashdown of Space Exploration Technology’s (SpaceX’s) Falcon-9 First Stage I felt that I was witnessing an almost historic moment. Almost. When the first SpaceX Falcon achieves a soft-landing on land, then we’ll know that the real beginning of the Space Age has arrived. Widespread use of a reusable first stage will drive the costs of launch down by 70% from SpaceX’s already low value. To get lower, the volume of traffic to space must increase, but the hinted ~$40 million price-tag to launch 53 tonnes (~$800/kg) via the Falcon Heavy booster means a long expected space-technology starts looking viable: Solar Power Satellites or Power-Sats.

The dream of beaming continual solar-power from space to the ground, providing the first direct space-resource for terrestrial use, has been around in fiction since the 1940s and in serious physics-based proposals since Peter Glaser’s seminal paper in 1968[1], developed more fully by the series of studies conducted by NASA and the US Department of Energy from 1978-1980. One outcome of the NASA-DoE studies was the 1980 conceptual Reference Design which was the subject of a report to Congress by the Office of Technology Assessment. The Design described a 5 gigawatt Power-Sat, with an area of 55 km2 and a mass of 50,000 tonnes, which would convert raw sunlight into microwave energy and send it to Earth at efficiency of just 6.7%. Part of the system inefficiency was the assumed 13% efficiency of the photovoltaic cells used.

Since the late 1970s the efficiency of photovoltaic cells have improved, especially in so-called multi-junction cells, which use multiple layers, each tuned to a different part of the spectrum. Combined with concentrating optics, which focus the light onto the cells, the efficiency of lab cells is presently pushing 45%. Wired up into an array and they might achieve ~37% efficiency. Newer light-to-electricity concepts seek to improve upon even that high mark. Here’s an example. A new preprint, by Manor, Martin & Rotschild, describes a way of pushing photovoltaics to 69% efficiency by using heat as well: http://arxiv.org/abs/1404.7345

..............//snip

SpaceX expect to slash the cost of Space Launch by 70% with reusable 1st Stages. Imagine the Falcon Heavy lofting 55 tonne SPS modules. Part of the array opens up to power an electric propulsion system, using 5 tonnes propellant for a GEO transfer. Once in the correct orbit it opens up fully, like a field of solar flowers. Eight components are lofted, meeting up and joining together to form a 1 GW Power-Sat, sending 2 GW of microwave power Earthwards, which is picked up by a Rectenna Farm – a field of conducting wires on poles, with crops growing underneath. After factoring in all the losses, the system supplies 1 GW of totally carbon-free power to the grid. 24 hours a day, 7 days a week – even in bad weather and at night. No gigantic banks of flow-batteries needed and no vast tanks of molten salt to store heat for night-time power supply. Sold at an average rate of $0.10/kilowatt-hour that 1gigawatt from space earns $877 million/yr. Over a 15 year lifetime it might earn ~$13 billion (constant $). Space Launch and construction costs need to be some preferably small fraction of that, to produce a significant Return-on-Investment (RoI). That’s where robotics is needed, but there will be some need for manned maintenance, perhaps via teleoperated machinery, which is advancing all the time.

My DU colleague, Bananas, has reported on work toward solar power satellites, mostly in Japan. SpaceX may give US companies a chance to participate in the effort.

[Uncle Joe]

1. Kicked and recommended.

Thanks for the thread, LongTomH.

[wandy]

2. Excellent, and at the same time Virgin Galactic explores a different method...........

http://www.youtube.com/user/virgingalactic

May they both succeed.

[daleanime]

3. K&R....

[bananas]

4. I am really looking forward to this.

When the first SpaceX Falcon achieves a soft-landing on land, then we’ll know that the real beginning of the Space Age has arrived.

[LongTomH]

6. Bananas, have you discovered Icarus Interstellar yet?

http://www.icarusinterstellar.org/

And, they have a Facebook page: https://www.facebook.com/groups/icarusinterstellar/

[bananas]

8. I came across them a while back.

We'll need either fusion or power-beaming for interstellar travel, which is another reason for research in those fields, even if they don't pan out for electricity on earth.

[LongTomH]

5. How did I miss adding the link?

[bananas]

7. Ongoing research at the US Naval Research Labs

An article from March:

http://www.nrl.navy.mil/media/news-releases/2014/solar-power-when-its-raining-nrl-builds-space-satellite-module-to-try

Solar Power When It's Raining: NRL Builds Space Satellite Module to Try
03/12/2014 07:00 EDT - 12-14r
Contact: Kyra Wiens, [phone]

What if you could capture solar power in space, then send it down to Earth? What if you could launch the hundreds of modules for such a satellite, then use robots to assemble the entire array in space? You could power a military installation, a city—even on a cloudy day, even at night.

At the U.S. Naval Research Laboratory (NRL), some of the brightest and most daring minds in satellites, space robotics, and radiofrequency are building the technologies that could lead to such an achievement.

<snip>

"In terms of the other applications," he adds, "the space radar is an obvious one." Jaffe's concept of building large structures in space from modules applies to large phased-array radars. "The image quality of a radar is related to how big the antennas are and how much power the radar puts out," he explains. With many antennas, each powered by the sun, "you don't have to have a huge, heavy bundle of wires that spreads out to each one of them."

Other applications include the conversion of direct current to radiofrequency, microwave power beaming (including as first demonstrated in 1964 to power an aircraft), satellite propulsion, and thermal management architecture (the step module).

<snip>

[LongTomH]

9. Thanks, Bananas! I'm glad someone in the US is still working on the concept!

Now, if we could just get a US Congress that isn't wholly owned and operated by Koch Industries and Exxon/Mobil, maybe we could get a pilot project, or just US participation in the Japanese effort.