on for 24 hours. kids can run or walk in their pajamas as you can see there if they want to. whatever gets them to participate. they look exhausted. it was cold. thc "nightly news" is next. t ore 6:ne mws at 6:00. good night. paying tribute, an emotional day in joplin, missouri, as president obama comforts another devastated american city. >> we will be with you every step of the way until joplin is restored and this community is back on its feet. on the road again, the sarah palin show rides into washington and beyond. just what is she really up to? also, war and remembrance, on this memorial day weekend, remembering americans who are serving tonight, and those who have sacrificed so much for serving tonight, and those who have sacrificed so much for their country. captions paid for by nbc-universal television

good evening, everyone. amid one of the most destructive tornado seasons in decades, president obama traveled to joplin, missouri, today to see the devastation for himself, and to honor the lives of those killed there, one week ago tonight. it was an all too familiar journey for the president, who just one month ago made a similar visit to tornado-ravaged tuscaloosa, alabama. in joplin today where at least 139 died and 40 people remain unaccounted for, survivors poured their hearts out to the president. he, in turn, reminded them that what happened to their community is a national tragedy. nbc's ron allen is in joplin with more on the president's visit. ron, good evening. >> reporter: good evening to you, lester. yes, it was a very powerful and emotional day here set against the stark backdrop of all this devastation and so many lives lost. the president said he admired

the resolve of people here to recover and he promised them the nation would be behind them every step of the way. >> how are you guys doing? >> reporter: walking the streets of an eviscerated neighborhood, president obama took a good, hard look at what one of the deadliest tornadoes the nation has ever endured had done. >> when we were in tuscaloosa a few weeks ago i talked about how i had not seen devastation like that in my lifetime. you come here to joplin, and it is just as heartbreaking and in some ways, even more devastating. >> reporter: the president was here as joplin came together by the thousands, for a memorial service exactly one week after the storm. >> that storm, the likes of which we have never seen, has brought forward a spirit of resilience, the likes of which we've also never seen. >> reporter: the president promised an appreciative audience he has no doubt joplin will rebuild. >> and as president, i can promise you, your country will

be there with you every single step of the way. we will be with you every step of the way. >> reporter: it's been a familiar task for the president this spring, with recent visits to flood-ravaged tennessee and storm-stricken alabama. here the president apparently tried to head off any criticism for being in europe this week while america's heartland suffered. >> we had world leaders coming up to me saying, "let the people of joplin know we are with them. we're thinking about them. we love them." >> reporter: the president highlighted acts of heroism by dean wells, a home depot manager who lost his life while saving customers and co-workers, and christopher lucas, who guided a dozen people into a freezer at a pizza hut and died trying to keep the door shut from outside, examples the president urged everyone to follow. >> let us live up to their example, to make each day count,

to live with a sense of mutual regard, to live with that same compassion that they demonstrated in their final hours. >> reporter: as the president said his good-byes, many were grateful as they faced the daunting task ahead. also here this evening, a moment of silence to mark the exact same one week ago when the tornado struck and people here say that everything changed. many people also now consider this to be hallowed ground, where self-reliant and somewhat stubborn people are determined to carry on. lester? >> ron allen tonight thank you. on paper joplin is a city of 50,000 but now it is finding the community that surrounds it extends much wider than anyone knew. strangers from far away have come to share the burden of putting joplin back together again. nbc's charles hadlock reports.

>> reporter: all across the scattered ruins of joplin today there are signs that somehow the city will survive. st. johns hospital reopened today, next to its battered building, in a special mobile hospital that can handle up to 60 patients. >> our time line is to try to rebuild a new brick and mortar hospital complex within two years. ♪ >> reporter: across town members of the peace lutheran congregation lost their church but not their faith. they pulled a mangled chalice out of the rubble and gathered for services on the parking lot next to the pile of debris that was once their church building. >> i know this goes for all of joplin, we plan on rebuilding joplin. this is our home. >> reporter: memorial day weekend is no holiday for the people of joplin but for the thousands of volunteers who have come here from across the country, it's the perfect time to help. christina ripka drove here from chicago with her son, james, who saw the devastation on television. >> the first night i've ever

cried in probably a couple years or so. >> says "we need to go down, mom, i want to make a difference." >> reporter: so they are cleaning the yards of people they don't even know, one handful at a time. >> what good is sitting in your backyard having a barbecue this weekend when you have people who don't have a backyard or a bed to sleep in tonight. >> reporter: rich blaney and his wife, deedee, brought their chainsaws from their home in montana. they felt they needed to do something. >> we appreciate all the help the government is going to give but there's not enough people in the government to help something like this. everybody has got to pitch in together. >> reporter: and together students from across missouri who were here to help found flags in the rubble and they hoisted them as a symbol that this city is not forgotten. charles hadlock, nbc news, joplin, missouri. >> and after all that tonight we are following yet more severe weather on this long holiday weekend, heavy thunderstorms hit northern illinois this afternoon, leading to the cancellation of 450 flights at

chicago's o'hare airport. the weather channel's kelly cass joins us with more. kelly, good evening. >> hi, lester. that same complex that affected chicago by the way, is still on the go this evening. we're watching it race across portions of michigan as well as ohio. a tornado watch goes until 8:00. a new severe thunderstorm watch back towards kansas and oklahoma wsere things are starting to pop as well. the immediate concern right now just to the east of detroit, moving across north central ohio and on its way to cleveland. there could be some serious winds with this. any trees reports of being toppled with these winds in excess of 70 miles an hour so there's your threat for tonight, watching minneapolis, back towards sioux falls, wichita for the overnight hours as well but unfortunately, lester, we think it's only going to get worse tomorrow. there could be another tornado outbreak as we get into memorial day and we're talking about the twin cities, towards sioux falls, lincoln, nebraska, towards concordia, kansas, severe weather is likely here with damaging winds and large hail, otherwise across the rest of the country, pick your beaches across the south, it is going to be sunny and very warm, so at least there it's going to be very nice but again tomorrow, have a way of being notified if in case you are being placed

under a warning. back to you, lester. >> kelly cass, the weather channel, thank you. >> the last thing we want to hear tonight, hurricane season we should tell you begins wednesday. to politics now and the question, just what is sarah palin up to, as the presidential campaign starts to heat up. whatever her intentions, her public life is being highly choreographed, including a stop in washington today on the back of a motorcycle. nbc's kristen welker has more tonight. >> reporter: sarah palin rolling back into the spotlight sunday, kicking off her east coast bus tour at the annual rolling thunder veterans bike run in washington, d.c., but still not answering whether she'll run. >> we're here to honor our vets and here to remind our americans how extremely important it is to express our gratitude. >> reporter: after leaving the rolling thunder rally she'll stop at iconic places like gettysburg, the liberty bell, the statue of liberty and ellis island, up to boston harbor, all

the with a i to new hampshire. the tour, paid by palin's action committee, is fueling speculation about what exactly she's up to. >> the bus tour is a promotional exercise being mistaken by some as the possible prelude to a presidential campaign. >> i don't see sarah palin getting into the race at all. i don't think there's a place for her. >> reporter: her former running mate john mccain believes she could beat the president. >> of course she can. she can. whether she will or not, whether she'll even run or not, i don't know. >> reporter: with palin shaking hands in the nation's capital, many gop insiders are likely scratching their heads, after all, a palin run could shake up a republican field that is slowly starting to take shape. former minnesota governor tim pawlenty is in and former massachusetts governor mitt romney officially launches his campaign next week. texas governor rick perry says he's mulling it over. >> i'm going to think about it. but i think about -- i think about a lot of things. >> reporter: tea party favorite michele bachmann and former

governor jon huntsman are undeclared and making the rounds. palin is the wild card. >> her entry could mix it up to the point where it denies pawlenty a clear path to victory but i don't think she'll get in. i think the nominee will be pawlenty, romney or huntsman. >> reporter: palin's tour could be the clearest sign yet that she just might be considering a bid. kristen welker, nbc news, washington. for more politics on the palin factor, we're joined by cnbc's chief washington correspondent john harwood. john, she's got us all talking which is probably part of what sarah palin is looking for. does this go beyond pr for a tv personality or are we watching a campaign for president? >> i think there's a good chance of preserving her voice and her brand. the first thing to know about sarah palin, she has given her negatives nationally in this country. she has next to zero chance of being elected president,

probably can't even be elected to win the republican nomination but what she probably could do, as fred malik suggested in kristen's piece is deny tim pawlenty to consolidate support on the right as an alternative to the establishment front-runner, and that's mitt romney. >> she's sucking up oxygen in the room, just after we finished watching the donald trump will he or won't he game. >> donald trump lent an air of chaos to the republican race. they don't need any more of that. republicans also don't need to absorb sarah palin's national negatives in this race. i think what republicans hope most is that sarah palin clarifies before too long that she's not going to get into this race, but what we know is the same rules don't apply to her as apply to other people. she's so well-known, has so much influence and clout on the right, she could get in much later than a conventional candidate. >> john harwood thank you very much for your insight tonight. when "nbc nightly news" continues tonight, america at

war, richard engel on the front lines with a look at the sacrifice americans are making in three conflicts. s

a changing of the guard is coming at the top of the defense department. tomorrow president obama is expected to nominate general martin dempsey as chairman of the joint chiefs. he would replace admiral mike mullen with general robert gates is being replaced himself next month by cia director leon

panetta. the new leaders will inherit responsibility for this country's involvement in two long wars, iraq and afghanistan, as well as the u.s. mission in libya. tonight richard engel reports on america's complicated role in these conflicts. >> reporter: a deadly fight with the taliban in afghanistan, a stability operation in iraq, and a support mission in libya. american troops are at war on three fronts, 150,000 in harm's way. especially in the longest war in u.s. history, afghanistan. last thursday, eight americans were killed while on a foot patrol in kandahar in a roadside bomb attack. >> we love the troops. why do we love the troops because we don't have to be the troops. we have a small number of americans defending 310 million people. it's easy to forget them. but we shouldn't forget them. today's a good day to remember that we have troops in combat.

>> reporter: u.s. troops are supposed to start gradually drawing down from afghanistan this july. >> the united states is conducting an operation that killed osama bin laden. >> reporter: after the killing of osama bin laden, there's increasing pressure to leave more quickly. in iraq, the combat mission ended last year, but nearly 50,000 american troops remain as advisers who are supposed to leave at the end of this year. the iraqi government might ask for some to stay. already shiite militias are returning to the streets. they'll likely grow stronger after u.s. troops are gone. the u.s. role in libya is far more ambiguous. the united states is backing nato, which is backing rebels, who are unable to advance on tripoli. the nato bombing campaign here in tripoli is sporadic, once or twice a day, and not every day, but the war in libya could soon escalate. the uk and france have both said they will send attack helicopters which can launch

more frequent precision air strikes, but the u.s. military doesn't appear to want to become more deeply involved. and it's unclear what would happen if gadhafi were killed. >> what do you do when there is no control and order and now we have evidence that gadhafi has armed the population in tripoli and the western parts of libya? it's a very dangerous situation. >> reporter: the u.s. military on this memorial day is fighting three wars, and none of them has an easy exit. richard engel, nbc news, tripoli. when we come back here tonight, the big business of flying high. it's the new space race.

the scene up above today as the shuttle astronauts floated out of the space station and back into "endeavour" for their trip home. with just one more shuttle mission to go before the program ends this summer, a new space race is already well under way. nbc's tom costello has that story. >> it's one small step for

man -- >> reporter: more than 40 years since the u.s. won the first space race with the soviets, the second space race is uniquely american. >> "endeavour" -- >> reporter: with the space shuttle fleet retiring this summer, private industry is battling to win nasa's confidence and the job of transporting astronauts to the space station and a company called spacex may be in the lead. >> we have liftoff of the falcon 9. >> stage one. >> reporter: already it's launched a rocket named falcon 9 with the spacecraft named dragon, orbiting the earth, separate rocket stages and splashed down in the pacific. >> we intend to take the dragon all the way to the space station, dock it, unload it and bring it back. >> reporter: a space station supply mission could come as early as this year, a manned mission in three to four years and spacex isn't alone. boeing is developing an apollo style rocket system. colorado based sierra nevada

pushing its dream chaser space plane, and blue origin founded by amazon.com's founder jason besos kept its plans largely secret. charles bolden now runs nasa. >> the race is on and i think more and more companies now are seeing that we're serious about relying on them to provide access. >> reporter: already nasa has provided $318 in seed money for the private sector to develop a modern alternative to the aging space shuttle fleet. by turning the job over to private companies, nasa is hoping to focus on the next frontier, developing the rockets to take astronauts to moving asteroids and maybe even mars. meanwhile, tourists could be hitching a ride to space in just 18 months. virgin galactic plans to charge $200,000 round trip. ceo richard branson says business will prove that space travel can be done more safely and cheaply. >> now you'll have a number of us who will be out there trying

to prove that we can do it better. >> reporter: for the next few years, nasa astronauts will be riding to space with their russian colleagues. as america's second space race kicks into high gear. tom costello, nbc news, cape canaveral. it was a tense and thrilling finish to the indianapolis 500 today. one turn away from winning, j.r. hildebrand lost control and skidded into the wall. allowing dan weldon to claim victory, his second indy 500 win. by the way, this was the 100th anniversary of america's most famous race. big box office weekend, the victory this weekend, winner is "the hangover part two." warner brothers estimates the sequel will take in $86 million this weekend, that's almost twice as much as the original made when it opened two years ago, helping put hollywood on track to set a new record, this long memorial day weekend. up next tonight, paying tribute to those who served long ago and gave so much for their country.

the aircraft carrier "john f. kennedy" before it was decommissioned four years ago, today on what would have been president kennedy's 94th birthday, the navy said the next u.s. air carrier will also be named "john f. kennedy" in honor of his service in world war ii. that brings us to the story of veterans of world war ii on this memorial day weekend. recently two dozen service members from tennessee and mississippi ranging in age from 83 to 95 got to make a special pilgrimage to washington to see the world war ii memorial, their memorial, for the first time. they arrived to a hero's

welcome, 66 years in the making. marines, army infantrymen, and air 4 gunners, even a few women who served, known as waves and whacks, to the crowd, there was just one name for them, heroes. >> couldn't imagine anything like this before. in fact it was a greater welcome than i got when i came back from europe. >> private parnell, you have not changed a bit. >> reporter: it's been a lifetime since they flew over the targets, stormed the beaches, and won the big one. >> hello, my world war ii warriors. >> reporter: but it all comes flooding back on the bus with an old-fashioned mail call. >> but mail call can get 'em up. >> pat patterson. >> some of these letters bring tears to a glass eye. >> never let 'em see you sweat but i'm sweating right now. >> reporter: at the only

national monument erected in their honor they remember friends who didn't make it home. 400,000 died in the war. [ "taps" ] >> reporter: olin pickens was a p.o.w. for over two years. >> they told us we'd be either killed or captured. i found out later 75 of our men got killed. >> reporter: bill drury was a tailgunner on the green hornet. he says his crew was as close as brothers. >> i accept this honor on their behalf. >> reporter: milton parnell was a member of the 783rd police. >> just thinking about what the world lost. >> nice to meet you. >> reporter: they were overwhelmed by the gratitude of fellow americans. >> i'm just so taken aback people come up to you, thank you for your service and i don't feel like i did that much.

i just feel like it was my duty, and i was proud to do it. >> reporter: the vets' trips are completely paid for and arranged by the senior wish nonprofit forever young. >> it is a time of healing for these men and women. they are dying a thousand a day, and we are just working so hard to honor them while they're still here. >> reporter: bonnie landon was a medic at a fleet hospital in hawaii. >> i think about them boys it was really sad, but so many of them was good and funny and you know something? they always had a sense of humor. >> reporter: humble heroes, finally bearing witness to the finite proof their legacy will not be forgotten. >> as mad as it was over there, we would do it again to save our freedom. [ "taps" ] >> and our thanks to those men and women and for all americans who serve and have sacrificed for this country.