Print 59 comment(s) - last by sigilscience.. on Mar 3 at 4:49 PM

NASA still unsure how to end Constellation and move forward

NASA has been plagued with financial issues and a continued lack of innovation, but now faces the equally daunting task of leaving behind the Constellation program.

President Obama and numerous space observers have been appalled at how poorly operated NASA has been in the past, with internal struggle and political opposition expected to make change even more difficult.  NASA Administrator Charles Bolden has garnered support from some politicians who said the White House is doing whatever it likes instead of working with experts.

As part of the agreement to end Constellation, NASA is expected to pay $2.5 billion to contractors already working on the Ares Rockets, Altair lunar lander, and Orion space capsule.  However, it's unknown how accurate the $2.5 billion estimate is, even though NASA relied on its own analysts and industry analysts to calculate the price.

NASA originally hoped to return to the moon by 2025, as other space nations plan to send lunar spacecraft and manned missions in the same time frame.  China, Japan, Russia, India, and several other developing space programs have expressed interest in landing on the moon by 2030 -- space industry observers think China will be the next country to reach the moon.

The 2011 budget has likely ended any chance of NASA returning to the moon, with private companies expected to help transport astronauts into space.

President Obama must now try to limit ongoing bickering as he works with NASA, private contractors, and legislators during his presidency.  The U.S. space agency will now rely more on the private contractors until current funding problems are sorted out in the future.

Comments     Threshold

This article is over a month old, voting and posting comments is disabled

RE: The moon
By porkpie on 3/1/2010 11:49:02 PM , Rating: 3
"Why do you think Spacex went with a Kerosene/Lox engine with an isp of 304 compared to a Hydrolox engine like the SSME with an isp of ~450. Cost."

And finally to correct this error. RP-1 (kerosene) rockets aren't used just because kerosene is cheaper. They're used because a) they have a significantly higher thrust than H2, b) a higher Isp per unit volume than H2, c) they're safer (about 1/4 the explosive hazard), and d) more reliable (no need for refrigeration, except for your oxidizer if you use LOX).

The real kicker is the higher thrust and higher Isp-density, though. Under many scenarios, that can actually give an RP-1 based rocket better performance than H2, once you factor in drag and parastic tankage losses into your mass fraction.

RE: The moon
By randomly on 3/2/2010 6:59:48 AM , Rating: 2
There was no error. You are missing the point.

It might have been a little more obvious if I had asked why Spacex uses a Kerolox engine for their upperstage engine. A HydroLox upperstage would about double their payload capacity, yet they don't use one. Why is that? Because it doesn't currently make business sense due to the overall costs vs the needs.

I'm well aware of all the technical pros and cons of LH/LOX vs Kerolox engines but these are all subordinate details to the overall goal of minimizing cost to orbit for the mission requirements. Higher performance is not an advantage if the total system cost increase outweighs the performance advantage. Reusable rockets are not an advantage if their operating costs are higher than expendables.

You are making the same mistake as was made on the Shuttle. A high performance but very expensive reusable system is not a cost effective approach compared to expendables if you cannot achieve high enough flight rates to give it a cost advantage. We don't have the money to achieve anywhere close to the kinds of flight rates needed.

Real rocket designs are driven by overall COST concerns, not just by technical performance.

RE: The moon
By porkpie on 3/2/2010 7:50:08 AM , Rating: 2
So far you've done nothing but talk wildly, gotten several basic facts incorrect, and misrepresent the supporting data I've given -- all without giving any of your own.

A huge number of noted physicists and aerospace engineers have concluded that nuclear propulsion offers far more promise than chemical. It doesn't take much intelligence to understand why...even the worst nuclear engine we can build offers twice the performance of the best chemical one. With a little additional engineering, nuclear rockets can best chemical ones by an 8:1 or better Isp ratio, which calculates into payload:fuel ratios a thousand times higher.

It's easy to understand why The Space Shuttle never achieved a high flight rate. Look at the design -- strap on boosters, an external tank, tens of thousands of incredibly fragile thermal 7 different flavors, no less. All sitting on top a pile of the most highly explosive fuel you can imagine, and tied to thrusters that can't be shut off once started. It's a nightmare.

None of that is necessary with a nuclear SSTO. The design is far simpler...and the massive performance advantage allows you to build a much stronger frame that doesn't ride so very near its design limits.

The Shuttle, for instance, experiences g forces of slightly over 3, and is only designed for a limit of 5g. That right there violates the basic "2:1 or more" safety factor engineers prefer to design around. The Shuttle also experiences heats of up to 3000F, which causes a multitude of maintenance, degradation, and safety issues. Again, this would not be necessary on a high-performance NTR.

Now, do you have anything from a reputable source to counter anything I'm saying?

RE: The moon
By porkpie on 3/2/2010 7:56:49 AM , Rating: 2
"I'm well aware of all the technical pros and cons of LH/LOX vs Kerolox engines but these are all subordinate details to the overall goal of minimizing cost..."

The Saturn V was fueled with kerosene. Do you actually believe that NASA -- in the heady days of the Apollo program -- was trying to pinch pennies?

I've already demonstrated to you the large number of reasons why RP-1 is a preferable fuel to H2 in many situations In designs like SpaceX's Falcon (or the Sat V), RP-1 gives you a higher performance envelope, due to the

In fact, The Shuttle's own SRBs don't even use H2 -OR- kerosene, but simple aluminum powder as fuel...a mixture that gives a lowly Isp of less than 250s. Why? Thrust, man, thrust.

RE: The moon
By randomly on 3/2/2010 2:19:14 PM , Rating: 2
You are rambling about commonly known aspects of propellant technologies but still completely missing the point.

Which particular technology is chosen for a particular application is driven by how it IMPACTS THE OVERALL COST OF THE PROJECT.

Higher performance options are not always the best choice if the performance advantage is outweighed by the increased overall costs they incur.

Spacex uses a Kerolox upperstage engine because of COST reasons not performance.

I repeat my original point that it is not clear at all that using NTR for LEO access makes any economic sense given foreseeable budgets and lift requirements.

NTR for earth departure stages is another matter, but for LEO access no country is seriously working on NTR designs anymore.

RE: The moon
By porkpie on 3/2/2010 6:29:05 PM , Rating: 2
"Spacex uses a Kerolox upperstage engine because of COST reasons not performance"

Did NASA use kerosene for Saturn V because of cost? Did they use aluminum powder to fuel the Shuttle SRBs because of cost?

Compared to the cost of a launch itself, the price differential between kerosene and liquid H2 is minimal. The real issues here are performance, safety, and reliability.

"If they're going to pirate somebody, we want it to be us rather than somebody else." -- Microsoft Business Group President Jeff Raikes
Related Articles

Most Popular ArticlesAre you ready for this ? HyperDrive Aircraft
September 24, 2016, 9:29 AM
Leaked – Samsung S8 is a Dream and a Dream 2
September 25, 2016, 8:00 AM
Inspiron Laptops & 2-in-1 PCs
September 25, 2016, 9:00 AM
Snapchat’s New Sunglasses are a Spectacle – No Pun Intended
September 24, 2016, 9:02 AM
Walmart may get "Robot Shopping Carts?"
September 17, 2016, 6:01 AM

Copyright 2016 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki