I may be misrepresenting Van Allen without reading his article in full, but the Summer issue of www.issues.org isn't up yet. I'll presume that www.space.com writer Leonard David has the gist of it.

The calm debate on space prospects has been going on since Apollo, and anyone who does some calm research will find it. In summary:

(1) If we limit the discussion to what has been done and can be done with rocket launchers of the present type, Van Allen is very nearly right. Automated missions are quicker and cheaper for most of the scientific investigations we want to make at present. However if all our missions are to be designed, built and directed from Earth, there are limits to their flexibility.

(2) But meanwhile, actual progress in or toward ...

(a) Electromagnetic mass accelerators
(b) Beam launch (microwave or laser)
(c) Space tethers
(d) Rockets using advanced materials

is such that we can reasonably extrapolate to a time, say 10-50 years, when some combination of these will reduce mass costs to orbit, to a point where some human missions are as cheap as some robotic missions are now. When we reach that point, we will enjoy the power of robotics and on-site human engineering (plus the accumulated knowledge of Earthbound humanity) in combination, and be able to do tremendously effective science. That alone will mandate a Martian expedition sooner or later - it will be cheaper than programming robots over light-minute lags.

(3) But this is only an appropriate view if we confine ourselves to pure science over the short term. Without making any special assumptions, what is practicable in 50 years is nearly inevitable in 100. Someone will do it, for sure; and when they do it they'll open the gates to industrial uses of space resources.

"Calm"  does not mean "myopic".

Van Allen also has not addressed the debate on space solar power (SSP) and space colonies, ongoing since the mid-'70s, and in my opinion so moderately presented that these days it has slipped below the public radar. Briefly, it is argued that the ability to put something on the order of 10,000 tons on the Moon is the ability to build an infrastructure which will eventually provide all Earth's energy needs.

The late Gerard O'Neill very calmly and quantitatively made that case in 1974, for both colonies and SSP; David Criswell is making it for SSP right now.  Robert Forward, R.P. Hoyt, Hans Moravec and numerous others have mapped out options for tether systems able to transport mass in the 10,000 ton range from LEO to Lunar surface. Lately Jordin Kare and Kevin Parkins have reported that beam-launch systems (laser and microwave respectively) in the range of 10,000 tons to LEO per year are within engineering reach given 30 years to scale up existing technology (launch cost about $200/kg). We also have Bradley Edwards' remarkably elegant space-elevator concept, and recent report that if there are serious obstacles to it, material strength is not among them.

If Van Allen is not addressing these peoples' work, calmly and quantitatively, then he is not seriously in the debate. If he thinks that the debate has stood still since Apollo and is strictly about planting flags on new destinations, then he is thirty years out of date.

Sadly, NASA is not publically in the debate either. I believe this is for the tenable reason that NASA's chief is forever in the position of endorsing what the Administration finds it possible to fund - and underlings are not expected to out-vision the chief. I consider President Bush's latest proposals - including a Moonbase and interplanetary nuclear propulsion - to be a decent working compromise. I'm skeptical about Mars as a priority, but I think we need a few years to see how that shapes up.

If Van Allen were only taking a position against an Apollo-style Race to Mars, I would agree with him. Enhancing robotics capabilities should be a prior step, and is better suited for engaging widespread academic and commercial efforts. But if he's arguing that human missions should be left out of the equation indefinitely, then events will leave him behind. Even to advance his own pure-science agenda, he should be backing the tether and beam-launch concepts.

But part of the long-term view of making space access more inexpensive is to get more opportunities to research ideas that scientists have proposed over the years about propulsion methods. The experiments with ion propulsion on NASA's Deep Space One probe were encouraging - the first in-space experiment using other than traditional chemical rocket propulsion worked. Let's try some of the others.

Once we have the opportunity to try, the path of invention probably will go in a different direction than we expect - it always does. Even just with routine access to low orbit, I'd be curious to see what inventions and changes occur.