International Space Station (Updates)

[Draggendrop Veteran]

LDSD postponed due to weather....

 

 

 

Mission managers have called off a weekend launch attempt for the Low-Density Supersonic Decelerators project due to low altitude wind conditions that would prevent the launch of the balloon. NASA will evaluate the next available launch opportunity, Monday, June 8. NASA

[Draggendrop Veteran]

Remote mechanical "handshake" completed.....

 

 

In the first-ever demonstration of space-to-ground remote control with live video and force feedback, NASA astronaut Terry Virts orbiting Earth on the International Space Station shook hands with ESA telerobotics specialist Andre Schiele in the Netherlands today.

Terry was testing a joystick that allows astronauts in space to 'feel' objects from hundreds of kilometres away. The joystick is a twin of the one on Earth and moving either makes its copy move in the same way. The joystick provides feedback so both users can feel the force of the other pushing or pulling. Earlier this year, NASA astronaut Butch Wilmore was the first to test the joystick in space but without a connection.

http://www.spacedaily.com/reports/Historic_handshake_between_space_and_Earth_999.html

 

 

 

Remote control
Landing astronauts on Mars and returning them home is a step too far for humanity at the moment, and operating rovers from Earth is difficult and tedious - it takes a command around 12 minutes to reach the planet. Instead, ESA envisages sending astronauts to orbit a planet and control robots on the surface from above.

With a gyro platform and tilt table, actual rover movements could be transferred to a controller...get the feel of spinning wheels/tracks.......

[Draggendrop Veteran]

In this post, I thought It would be a good time to talk about the ISS EPS, Electrical Power System. This is one of the most complex systems on the station, but we can tackle this in stages that, "hopefully", will be a little more entertaining than watching paint dry.

 

To begin, the ISS orbits approximately 220 miles (407 km) above the earth. It's orbit is roughly 52 degrees to the equator. It takes the station 90 minutes to complete an orbit, of which 35 minutes is in eclipse (dark). The solar generating system supplies 84 kw to 120 kw to the station. The nominal 84 kw is stated in most instances. While in the generating phase of the orbit, the EPS supplies required power to the station for equipment and 60 percent of total output is used to charge batteries which take over the full load on the "dark" side. During transit in orbit, the solar arrays must have their "plane" adjusted orthogonal (90 degrees) to the received solar energy for maximum collection, This tracking must be continuous through out the orbit.

 

Above the earth's atmosphere, the total power received is approximately 1500 watts per square meter. The solar cells used operate at roughly 20 percent efficiency. The Law of Conservation of Energy states that energy cannot be created nor destroyed, only converted into other forms.(Note some exceptions apply to nuclear processes). With this said, and a 20 percent conversion efficiency, reflected power and generated heat comprise the rest. The cells are also affected by surface contamination and mechanical "aging" due to ionization damage and thermal shocks in orbit. Each Saw is 110' x 38' and the ISS has an acre of solar panel surface.

 

We will start with a picture of the arrays....

 

There is a port assembly and a starboard assembly. Pick an assembly and we will see 4 wing sections composed of 2 side by side blankets. The side by side blankets are called wings or SAW's, solar array wings. 4 wings on port end and 4 wings on starboard end of the ISS. We will pick a blanket and "pick" at it.

 

A solar cell is 3" x 3" and 400 cells in series is called a string. Every 8 cells has a bypass diode to remove that section when damaged. 41 strings are in parallel and 16,000 cells per blanket. This makes 32,000 cells per SAW (wing) which will make up a channel. There are 8 power channels on the ISS.

 

Before we continue...power basics...primary power (rough) and secondary power (conditioned). Primary at the arrays is approximately 137 vdc to 173 vdc. Secondary power is 123 vdc to 126 vdc conditioned for load use. The usual power standard is 28 vdc but a change was required for the ISS.  8 miles of wire required weight reductions and the way to do this was to increase the voltage, which reduces the current for the same power level and therefore affords lighter gauge wiring and reduced weight.

 

Now for our next picture.....

 

In this picture you see 2 SAW's and an IEA, integrated equipment assembly. At the joints of the SAW's are beta gimbles which enables each individual SAW to be trimmed for one of the two orbital plane directions. The alpha gimble attaches at the station truss and rotates all 4 SAW's together through 360 degrees during a full orbit. Primary power leaves a SAW, to a channel, and goes through a SSU, sequential shunt unit which controls voltage levels across all strings, regulating output to approximately 160 vdc. From there, power goes through a DCSU, direct current switching unit, which direct power flow to the MBSU, main buss switching unit as well as to the BCDU, battery charge discharge units.

 

Each IEA measures 16' x 16' x 16' (4,9 m) and weighs 17,000 lbs (7;711 kg). There are 6 batteries in each IEA and each battery is actually 2 ORU's (orbital replacement units).

 

Next pictures, the battery and construction...

 

 

 

To save time typing...

 

A nickel

[Draggendrop Veteran]

Here are a few pictures of the Russian solar array....

 

April 3, 2013, partial of Russian array...

 

February 5, 2014, partial of Russian solar array...

 

SAW picture...

 

February 14, 2014...Nanorack Cubesat's being released from the Japanese Experimental Module...

[Draggendrop Veteran]

Most have seen this iconic photo...here's the details...

 

 

 

 

When the crew of Mission 41B

[Arachno 1D]

Interesting technology but with only 20% efficiency on such high end solar panels it seems we are a long way of being self sufficient on earth bound systems which lag way behind.

[DocM]

Solar City's new Buffalo NY gigafactory (opens ~2016) will produce 24% cells like sausages** and they & others have far better than that in the labs.

This is enough to fly crewed missions using solar electric propulsion (SEP) anywhere in the inner solar system (asteroid belt inwards), and be lighter than any currently produceable space nuclear reactor of similar power.

Solar City is also a sister company of SpaceX and Tesla, which is building an advanced battery factory in Reno, Nevada which will be almost 10 million sq/ft - about 230 acres/93 hectares.

Spacecraft + high efficiency solar + high power density batteries: a Tri-Fecta for exploration and colonization.

** at full production it's expected to double the worlds solar cell production.

[Draggendrop Veteran]

Interesting technology but with only 20% efficiency on such high end solar panels it seems we are a long way of being self sufficient on earth bound systems which lag way behind.

Doc's post is right on the mark. Solar technology is really taking off the last 5 years. Cells are around 24 % efficiency and units with concentrators are at 50%. There are many variation of cells from different elements being used in the substrates to multiple junction (conjugate) devices, various wavelength directors, intensifiers and concentrators, as well as flexibility. The trick is to keep the manufacturing costs down and that's well under way. 

 

The real issue has been energy storage...hence...affordable storage battery systems for solar and wind/wave generation. Solar city is about to change that with residential and commercial energy storage systems.

Many countries are realizing the benefits of green energy such as Denmark at 39.1 % total power is green. The UK, Germany. Scotland and Ireland are well on their way as well.

http://ecowatch.com/2015/01/09/countries-leading-way-renewable-energy/

http://phys.org/news/2013-02-multijunction-solar-cell-efficiency-goal.html#nRlv

http://cleantechnica.com/2015/01/16/solar-cell-efficiency-jumps-50-with-perovskite-layer/

http://cleantechnica.com/2014/12/03/new-solar-cell-efficiency-record-set-46/

http://phys.org/news/2014-12-nrel-efficiency-solar-cell.html#nRlv

 

The first piece of the ISS was put up in 1998, and the design for EPS was several years older than that....that's technology that is 20 years old. Systems today are much more advanced and location, whether it be on earth or in space, will both be efficient. But,... the ISS is a tough old bird...Cheers....

[DocM]

Solar City's power storage units will actually be from a new Musk company: Tesla Energy.

Their products,

Powerwall; a modular 7-10 kWh battery which can be arrayed for home use.

Powerpack: industrial 100 kWh units which can be racked for up to 500 kWh. Racks can be arrayed for up to a 10 mWh capacity.

These guys are SERIOUS.

[BetaguyGZT]

I was gonna jump into the discussion, but Doc and DD beat me to it.

 

20% efficiency is actually pretty good when you consider that those Solar Cells were first manufactured in 2000~2002. Today's design would probably use a different cell like Polycrystalline (the sapphire blue, multifaceted one although they can make them different colors now it affects the efficiency) with a special coating to protect it from the high-UV and low-pressure environment. Those cells have around a 20% efficiency for the Commercial Market but if they are specially (and carefully) manufactured they can see that number go up to as good as 40%. NASA and the ISS Partners would demand the "Special Version".

 

Here are reference images to show what those cells look like. They're spiffy.

 

 

Google Image Search - more Polycrystalline Solar Cells

 

[Draggendrop Veteran]

Found a picture of the Russian solar arrays. This picture was during initial assembly of the ISS...

 

 

This diagram lists the modules....

 

 

Here is a list, by year and mission, of the flights required to build the ISS...

http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Building_the_International_Space_Station3 

 

Found another ISS tracker...similar to previous link given for tracker...but...when communication are up...this one gives an HD camera view of earth...not on all the time...hit or miss for operation...

http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Where_is_the_International_Space_Station

 

The ISS is the 5th space station. This video takes you through the first four....with all the difficulties and solutions to make what we have today...long, but an eye opener...Cheers...

https://www.youtube.com/watch?v=NzSFOX2hoR0

 

[Draggendrop Veteran]

I was watching the lift-off of the Nasa LDSD, which went well at 1:45 EDT, will take 3 hours to get to altitude. While bored, I found this "trailer" which has an artificial gravity ring as we were discussing prior....

 

The Martian

 

 

and another...

 

[Draggendrop Veteran]

LDSD test ok. other than shute problem...

 

[flyingskippy]

It almost seems like the chute is too close to the LDSD, catching eddy currents coming off of the vehicle. These currents can be strong and violent causing the chute to tear and fail to open. I'm just a pilot though, not an aerodynamicist.

[Draggendrop Veteran]

It almost seems like the chute is too close to the LDSD, catching eddy currents coming off of the vehicle. These currents can be strong and violent causing the chute to tear and fail to open. I'm just a pilot though, not an aerodynamicist.

I would say you are qualified, you know the environment........other than that, a success for data capture...one more test will be done. This is the second test but the first one was a scale unit. I will look up when next test is due.....Cheers....

[flyingskippy]

I hope it is a simple fix (not likely with NASA). It hasbeen almost a year since the last LDSD test flight and the parachute failed pretty much the same way. This really is key for us to get larger payloads on Mars. At least we know the SIAD works.

[DocM]

Supersonic retropropulsion is the ONLY way to get a 25-50+ tonne payload down. Parachutes won't cut it. Even if they did their growing percentage of the payload mass would be impractical.

[BetaguyGZT]

Supersonic retropropulsion is the ONLY way to get a 25-50+ tonne payload down. Parachutes won't cut it. Even if they did their growing percentage of the payload mass would be impractical.

I agree. Doing this with a goofy "Superchute + Whatever Thingy" is no substitute for a good set of Retros and a Heat Shield. Those are tried and tested technologies that are proven to work. Certainly, use a set of 'chutes that are scaled to deal with Mars' atmosphere and the load for the last bit of the landing -- please, by all means do this and incorporate a failsafe to ensure the payload is delivered intact and mission-viable.

 

This LDSD system is not going to work, and never had a chance of working. Two back-to-back tests of the system with the same failure do NOT lie. The payload is too heavy and the speeds are way too high to use that large of a parachute, no matter what density the atmosphere is. They need to use smaller drogue chutes and then deploy larger ones when the speeds are lower. Yes, I mean it plurally -- parachutes. Using a single one for a payload that large is simply dumb and irresponsible, especially one that large going to Mars. There's so much left to chance and too much that could go wrong that I'd never sign off on a mission that called for using it.

[Draggendrop Veteran]

In my opinion, I think SpaceX has the right idea with Dragon V2. If a Mars  "Mothership" were to be in orbit, dropping V2's (or V2's on steroids) with technicians and equipment to get a fuel processing plant up and running.......we could concentrate on oxygen and water production for an outpost.....

 

SpaceX is going to Mars, and may make a few others look blinded.....

 

 

Edit...Nice Mars worksuits in the film trailer.....

[BetaguyGZT]

I agree. Send up several Multi-Purpose 3D Fabricators/Printers (with enough parts to build 3 more), Fuel Processing/Production, Chemical Electrolysis/Analysis, Inflatable Habitation Modules, Seeds to grow 4 cycles worth of crops (in case some fail), Technicians/Engineering/Science Crew, Supplies and Equipment, Computers, Solar Generation Equipment (Batteries and Panels), Food and Water .. essentials.

 

Sounds like a monumental task and it is. Test out all equipment and procedures on Earth first, tweak as needed; then at a Lunar Colony, tweak some more, then finally Mars Colony 1.

 

If anyone can do this, it's NewSpace. OldSpace had their chance to do it and they didn't, so I say let them sit on the bench and watch. Nobody needs their permission, do they?

[Draggendrop Veteran]

I agree. Send up several Multi-Purpose 3D Fabricators/Printers (with enough parts to build 3 more), Fuel Processing/Production, Chemical Electrolysis/Analysis, Inflatable Habitation Modules, Seeds to grow 4 cycles worth of crops (in case some fail), Technicians/Engineering/Science Crew, Supplies and Equipment, Computers, Solar Generation Equipment (Batteries and Panels), Food and Water .. essentials.

 

Sounds like a monumental task and it is. Test out all equipment and procedures on Earth first, tweak as needed; then at a Lunar Colony, tweak some more, then finally Mars Colony 1.

 

If anyone can do this, it's NewSpace. OldSpace had their chance to do it and they didn't, so I say let them sit on the bench and watch. Nobody needs their permission, do they?

Yes...basically the mothership can be a tug pulling resource modules...It appears the prime points are a fuel source once there and water...if we have water, we're generating oxygen.

[DocM]

If you have water for O2 and engine oxidizer you get H2 for free. Use it, the Martian atmosphere (mostly CO2) and apply the Sabatier process and you get methane. There's your fuel for whatever engine, rocket or IC..

[FloatingFatMan]

If you have water for O2 and engine oxidizer you get H2 for free. Use it, the Martian atmosphere (mostly CO2) and apply the Sabatier process and you get methane. There's your fuel for whatever engine, rocket or IC..

 

I'm no chemist (not even remotely), but can't you also split the O2 from the CO2 to make oxygen?

[DocM]

If you want to, by splitting CO2 into O2 and CO (carbon monoxide.) Supplement more O2 from water splitting and CO can also be used as s rocket fuel. Use the H2 to make methane. You can also use magnesium as a fuel and CO2 as the oxidizer, which was written up in an AIAA paper in 1993.

There are many other options.

[FloatingFatMan]

So the next question is, how practical is it to do this at a prospective Martian outpost, given today's technology.  Is the equipment needed small enough to transport, yet have a high enough yield to provide the resources necessary to sustain it?