JOHN: TONIGHT ON PBS NEWS WEEKEND, THE EASTER TRUCE FALTERS AS RUSSIA AND UKRAINE ACCUSE EACH OTHER OF LAUNCHING HUNDREDS OF ATTACKS.

THEN, WHAT ELIMINATING THE ENVIRONMENTAL JUSTICE OFFICES AT THE EPA COULD MEAN FOR POOR AND MINORITY COMMUNITIES.

AND, AFTER A DECADE MAPPING BILLIONS OF STARS ACROSS THE MILKY WAY AND BEYOND, A GROUNDBREAKING SPACECRAFT RETIRES.

>> WE WERE WITNESSING SOMETHING BIG THAT WAS ENDING, AND THERE WERE MANY EMOTIONS AND THERE WAS TEARS IN THE ROOM.

JOHN: GOOD EVENING I'M JOHN YANG.

TONIGHT RUSSIA AND UKRAINE ARE BLAMING EACH OTHER FOR BREAKING THE ONE-DAY EASTER CEASEFIRE THAT RUSSIAN PRESIDENT VLADIMIR PUTIN HAD DECLARED.

UKRAINIAN PRESIDENT VOLODYMYR ZELENSKY SAID RUSSIA NEVER CEASED FIRING AND ATTACKS CONTINUED AFTER PUTIN'S ANNOUNCEMENT.

RUSSIA SAID IT WAS UKRAINE THAT BROKE THE TRUCE, SHOOTING AT RUSSIAN POSITIONS AND LAUNCHING DRONE ATTACKS, KILLING CIVILIANS.

TODAY, THE STATE DEPARTMENT SAID THE UNITED STATES IS COMMITTED TO ACHIEVING A FULL AND COMPREHENSIVE CEASEFIRE.

WILLIAM TAYLOR IS A DISTINGUISHED FELLOW WITH THE ATLANTIC COUNCIL'S EURASIA CENTER.

HE WAS U.S.

AMBASSADOR TO UKRAINE UNDER GEORGE W. BUSH AND THE TEMPORARY HEAD OF MISSION THERE IN THE FIRST ADMINISTRATION OF PRESIDENT TRUMP, LATER TESTIFYING IN HIS IMPEACHMENT.

THIS CEASE-FIRE THAT ONE SIDE DECLARES AND DEVELOPS INTO FINGER-POINTING, WHAT DO YOU MAKE OF THIS?

WILLIAM: THEY ARE PROBABLY NOT SERIOUS.

PUTIN WAS NOT SERIOUS.

HE HAS DECLARED CEASE-FIRES BEFORE AND VIOLATED THEM.

ZELENSKY SAID 30 HOURS?

NO, 30 DAYS.

IF WE WANT A SERIOUS CEASE-FIRE DO THE CEASE-FIRE THAT PRESIDENT TRUMP AND PRESIDENT ZELENSKYY AGREED ON, A COMPREHENSIVE 30 DAY CEASE-FIRE OF AIR, LAND AND SEA.

IF YOU ARE SERIOUS MR. PUTIN, GO FOR THAT TYPE OF CEASE-FIRE.

JOHN: THE SECRETARY OF STATE AND PRESIDENT SOUNDED LIKE PATIENCE WAS RUNNING OUT.

PRES.

TRUMP: IF FOR SOME REASON ONE OF THE TWO PARTIES MAKES IT VERY DIFFICULT WE ARE GOING TO SAY YOU ARE FOOLISH, YOU ARE HORRIBLE PEOPLE AND WE WILL TAKE A PASS THAT HOPEFULLY WE WON'T HAVE TO DO THAT.

JOHN: IS THIS PART OF THE BARGAINING OR ARE THEY SERIOUS ABOUT WALKING AWAY?

WILLIAM: IF THE PRESIDENT IS IRRITATED AT ONE OF THE TWO WHO IS NOT SERIOUS, HE MUST BE IRRITATED WITH PUTIN.

WHICH WOULD BE UNUSUAL, BUT PUTIN IS THE ONE WHO SAID NO TO PRESIDENT TRUMP.

THE ONE WHO SAID NO, I WILL NOT ABIDE BY WHAT I AGREED TO.

HE HAS NOT BEEN BARGAINING IN GOOD FAITH.

PRESIDENT PUTIN IS DRAGGING THIS OUT BY ALL ACCOUNTS.

IF THERE IS ANYONE TO BE IRRITATED WITH, IT IS PUTIN.

IF THAT IS THE CASE, PRESIDENT TRUMP HAS SOME LEVERAGE TO PUT ON PUTIN TO BRING HIM BACK.

JOHN: DRAGGING THIS OUT TO WHAT END, PUTIN?

WILLIAM: SO THAT HE GRADUALLY TAKES MORE.

HIS GOAL IS TO CONTROL UKRAINE.

THAT IS WHAT HE STARTED DOING IN 2008, 2014, 2022.

IT IS TO CONTROL UKRAINE, WHICH HE THINKS IS NOT A NATION BUT PART OF RUSSIA, SO HE WANTS TO ELIMINATE UKRAINE.

THAT IS HIS GOAL AND HE THINKS HE CAN WAIT US AND THE EUROPEANS OUT.

HE THINKS THE UKRAINIANS MIGHT BREAK BUT THEY ARE NOT.

WE SHOULD NOT EITHER.

JOHN: SOME SAY WALKING AWAY WOULD BE A BENEFIT TO PUTIN BUT YOU DISAGREE.

WILLIAM: WALKING AWAY WOULD BE AN ADMISSION THAT ONE OF THE TOP PRIORITIES OF THE U.S. GOVERNMENT, THE NEW U.S. GOVERNMENT, IS IMPOSSIBLE TO DO.

PUTIN PROBABLY NEEDS THIS CEASE-FIRE.

HIS ECONOMY IS IN BAD SHAPE.

THE UKRAINIANS ARE EAGER FOR THE CEASE-FIRE AS WELL.

THEY HAVE BEEN FIGHTING FOR OVER THREE YEARS, HOLDING OFF THE RUSSIAN ARMY, AND HAVE BROUGHT THEM TO A VIRTUAL STANDSTILL.

THEY ARE TIRED.

THEY WANT THE CEASE-FIRE BUT DO NOT WANT TO BE UNDER RUSSIAN CONTROL, SO THEY WILL CONTINUE TO FIGHT UNTIL THEY CAN GET THAT CEASE-FIRE AND A SETTLEMENT THAT IS GOOD FOR THEM.

JOHN: WHEN SECRETARY RUBIO AND PRESIDENT TRUMP TALK ABOUT WALKING AWAY, IS IT JUST TO THE TALKS OR DO YOU THINK THEY WILL ALSO PULL SUPPORT FOR UKRAINIANS?

WILLIAM: THAT IS THE RIGHT QUESTION TO ASK.

WE HAVE SEEN WHAT HAPPENS WHEN THEY PULL SUPPORT WITH WEAPONS, INTELLIGENCE, IT IS BAD FOR UKRAINE.

THEY WILL CONTINUE TO FIGHT IN ANY CASE, BUT IF AMERICANS PULL OFF FROM NEGOTIATIONS, BUT CONTINUE TO SUPPORT THEM WITH WEAPONS, INTELLIGENCE AND DIPLOMATIC, THEN UKRAINE CAN CONTINUE TO MAKE IT.

JOHN: GIVEN YOUR EXPERTISE AND BACKGROUND, HOW DO YOU THINK THIS WILL PLAY OUT?

WILLIAM: I THINK UKRAINIANS WILL CONTINUE TO RESIST THE RUSSIANS.

I THINK PUTIN WILL CONTINUE TO TRY TO DRAG OUT THIS ADMINISTRATION, TRY TO DRAG OUT THIS FIGHT.

I THINK THEY WILL BOTH GET TIRED AND I THINK UKRAINE WILL MOVE ON ONCE THAT HAPPENS TO JOIN THE E.U.

AND RECONSTRUCTING WHAT IT CONTROLS AND EVENTUALLY JOINING NATO.

THAT IS A HARD ONE BUT I THINK THAT IS WHERE UKRAINE WILL BE.

AND RUSSIA WILL CONTINUE TO THREATEN.

JOHN: WHAT ROLE WILL THE U.S.

PLAY?

WILLIAM: I HOPE THE U.S. WILL BE SUPPORTIVE OF UKRAINIANS.

IT IS IN OUR INTERESTS, SO THAT RUSSIA DOES NOT CONTROL UKRAINE AND THREATEN EUROPE, WHERE OUR SOLDIERS ARE.

WE HAVE SOLDIERS THERE, AND THAT WOULD BE A THREAT TO THEM.

JOHN: THANK YOU.

IN TONIGHT'S OTHER NEWS -- THE ISRAELI MILITARY SAYS PROFESSIONAL FAILURES LED TO THE KILLING OF MORE THAN A DOZEN PALESTINIAN MEDICS IN GAZA LAST MONTH.

THAT'S THE CONCLUSION OF AN INTERNAL INVESTIGATION FOLLOWING THE DISCOVERY IN A SHALLOW GRAVE - - OF A SHALLOW GRAVE OF THE BODIES OF 14 RED CRESCENT MEDICS AND A U.N. WORKER.

THE REPORT SAID THE TROOPS WERE OPERATING IN A HOSTILE AND DANGEROUS COMBAT ZONE, AND THAT INVESTIGATORS FOUND SEVERAL PROFESSIONAL FAILURES, BREACHES OF ORDERS, AND A FAILURE TO FULLY REPORT THE INCIDENT.

INITIALLY, ISRAEL SAID TROOPS OPENED FIRE ON VEHICLES THAT WERE APPROACHING IN A SUSPICIOUS MANNER, BUT CELL PHONE VIDEO RECOVERED LATER FROM ONE OF THE VICTIMS SHOWED THE AMBMBANCES'S EMERGENCY LIGHTS WERE FLASHING.

ISRAEL HAS LONG ACCUSED HAMAS OF USING AMBULANCES TO TRANSPORT FIGHTERS AND WEAPONS.

THE ISRAELI MILITARY SAID A DEPUTY COMMANDER WILL BE FIRED FOR PROVIDING AN INACCURATE REPORT OF THE INCIDENT.

THREE STATES SAY THEY HAVE THEIR FIRST MEASLES CASES OF THE YEAR.

STATE HEALTH OFFICIALS IN MISSOURI, LOUISIANA AND VIRGINIA REPORT ONE CASE EACH.

THEY'RE NOT BELIEVED TO BE RELATED AND ALL STEM FROM RECENT INTERNATIONAL TRAVEL.

ACCORDING TO THE LATEST CDC NUMBERS, THERE HAVE BEEN 800 CONFIRMED MEASLES CASES THIS YEAR AND THREE DEATHS FROM MEASLES.

96% OF CASES INVOLVE PEOPLE WHO ARE UNVACCINATED OR WHOSE VACCINATION STATUS IS UNKNOWN.

POPE FRANCIS'S EASTER SUNDAY AT THE VATICAN WAS DIFFERENT FROM YEARS PAST.

HE DID NOT PRESIDE OVER EASTER MASS, BUT OFFERED A BLESSING FROM A BALCONY OVERLOOKING ST. PETER'S SQUARE.

THE PONTIFF ALSO BLESSED SOME CHILDREN IN THE CROWD WHEN HE DROVE AROUND THE SQUARE IN THE POPE-MOBILE.

THOSE GATHERED FOR THE HIGH HOLY DAY SAID THEY WERE HAPPY TO SEE THE 88-YEAR OLD RECOVERING FROM A BOUT WITH DOUBLE PNEUMONIA.

>> WHEN I WALKED UP HERE, I FELT VERY EXCITED TO SEE ALL THE PEOPLE HERE.

I HAVE NEVER SEEN THE POPE, SO IT'S VERY GREAT FOR ME TO SEE HIM.

I FELT A BIT EMOTIONAL SEEING HIM.

JOHN: THE POPE ALSO MET BRIEFLY WITH VICE PRESIDENT JD VANCE WHO IS IN ROME WITH HIS FAMILY.

THE VATICAN SAID THE TWO EXCHANGED EASTER GREETNGS.

- - GREETINGS READ AIDES PRESENTED VANCE WITH GIFTS FOR HIS FAMILY, INCLUDING CHOCOLATE EGGS FOR HIS CHILDREN, ROSARIES AND A VATICAN TIE.

AND, A U.S. ASTRONAUT CELEBRATED HIS 70TH TRIP AROUND THE SUN -- BY RETURNING TO EARTH.

>> AND TOUCHDOWN.

SOYUZ MS-26 IS HOME.

JOHN: ASTRONAUT DON PETTIT AND TWO RUSSIAN COSMONAUTS LANDED IN KAZAKHSTAN SATURDAY -- WHICH WAS PETTIT'S BIRTHDAY.

THE TRIO SPENT 220 DAYS ON THE INTERNATIONAL SPACE STATION CONDUCTING RESEARCH AND EXPERIMENTING WITH 3D PRINTING AND WATER SANITATION.

PETTIT WILL UNDERGO MEDICAL CHECKS OVERSEAS BEFORE GOING TO THE JOHNSON SPACE CENTER IN HOUSTON WHERE HE WILL RE-ACCLIMATE TO EARTH'S GRAVITY.

STILL TO COME ON PBS NEWS WEEKEND, WHAT CLOSING EPA'S ENVIRONMENTAL JUSTICE OFFICES MAY MEAN FOR POOR COMMUNITIES ACROSS THE COUNTRY.

AND, A STAR-MAPPING SPACE OBSERVATORY THAT CHANGED ASTRONOMY BIDS FAREWELL.

JOHN: FOR THREE DECADES, EPA OFFICES WERE ESTABLISHED NATIONWIDE TO ADDRESS THE DISPROPORTIONATELY HIGH LEVELS OF POLLUTION IN POOR AND MINORITY COMMUNITIES.

NOW THE TRUMP ADMINISTRATION IS ELIMINATING THESE ENVIRONMENTAL JUSTICE OFFICES AS PART OF ITS EFFORT TO END DEI PROGRAMS AND CUT WHAT IT SEES AS WASTEFUL SPENDING.

ALI ROGIN RECENTLY SPOKE WITH AMUDALAT AJASA WHO COVERS ENVIRONMENTAL HEALTH FOR THE WASHINGTON POST.

ALI: AMUDULAT, THANK YOU SO MUCH FOR JOINING US.

FIRST OF ALL, LET'S TALK ABOUT THE HISTORY OF THE ENVIRONMENTAL JUSTICE MOVEMENT AND HOW DID IT BECOME A PART OF WHAT THE EPA DOES.

AMUDULAT: YEAH, THE HISTORY OF THE ENVIRONMENTAL JUSTICE MOVEMENT REALLY RECOGNIZES THE FACT THAT EVERYBODY DESERVES ACCESS TO CLEAN AIR, WATER, AND THE LAND THAT THEY LIVE ON, RIGHT?

AND THAT WAS REALLY INTRODUCED INTO THE GOVERNMENT OVER 30 YEARS AGO BY BILL CLINTON.

HE RECOGNIZED THE FACT THAT THESE INEQUITIES NEEDED TO BE ADDRESSED AT THE GOVERNMENT LEVEL BECAUSE IT WASN'T HAPPENING ELSEWHERE.

IT DEVELOPED 30 YEARS AGO, BUT FOLKS REALLY FELT LIKE THEIR VOICES WERE HEARD UNDER THE BIDEN ADMINISTRATION.

ALTHOUGH SOME OF THEM FELT LIKE THE ADMINISTRATION DIDN'T GO FAR ENOUGH IN THE LEGISLATION THAT THEY DID PASS TO MAKE SURE THAT THEY HAD CLEANER AIR AND WATER, THEY FELT LIKE FOR THE FIRST TIME, THE RISKS THAT THEY FACED WERE REALLY ACKNOWLEDGED.

ALI: WHAT ARE SOME SPECIFIC EXAMPLES OF ENVIRONMENTAL JUSTICE POLICIES AT WORK AND THE TYPES OF PROBLEMS THAT THIS OFFICE SET OUT TO ADDRESS?

AMUDALAT: SOME OF THE POLICIES AT WORK REALLY LIMITED THE AMOUNT OF POLLUTION THAT INDUSTRY WOULD BE ABLE TO PUMP INTO THE AIR, THE SOOT THAT WOULD BE ALLOWED TO LINGER IN THE AIR.

OTHER SPECIFIC C CMICALS THAT THEY REALLY WENT AFTER, BENZENE AND OTHER THINGS THAT FOR FOLKS WHO LIVE IN CANCER ALLEY, THAT'S A DAY-TO-DAY REALITY FOR THEM.

ALI: AND TELL US ABOUT CANCER ALLEY.

WHAT IS THAT?

AMUDALAT: YEAH, CANCER ALLEY IS AN 85-MILE STRETCH IN LOUISIANA.

THAT IS FULL OF INDUSTRY, THAT IS PUMPING A LOT OF AIR POLLUTANTS, AND THESE COMMUNITIES ON THE FRONT LINE, THEY GET, THE NAME IS DUBBED CANCER ALLEY, BECAUSE FOR THEM, CANCER IS A REALITY.

A CANCER, YOU KNOW, IT'S EITHER SOMEBODY CLOSE TO THEM THAT HAS CANCER, SOMEBODY IN THEIR FAMILY, OR THEY KNOW PEOPLE IN THEIR COMMUNITY, SO THEY HAVE THESE HOT POCKETS OF NOT JUST CANCER, BUT OTHER HEALTH AILMENTS THAT, YOU NOW, THE NORMAL AMERICAN WOULDN'T BE DEALING WITH, BUT BECAUSE THEY'RE EXPOSED TO SO MANY CHEMICALS ON A DAY-TO-DAY BASIS.

THAT'S THEIR REALITY.

ALI: I WANT TO PLAY FOR YOU.

WE SPOKE TO A FORMER EPA ENVIRONMENTAL JUSTICE EMPLOYEE.

HE NOW WORKS AT THE NATURAL RESOURCES DEFENSE COUNCIL.

HERE'S HOW HE EXPLAINED HOW HE WORKED WITH COMMUNITY MEMBERS HE WAS SERVING.

>> WE HAD A TRIBAL COMMUNITY THAT WAS SURE THAT THE DRINKING WATER THAT THEY USED FOR THEIR FAMILIES AND FOR THEIR ANIMALS WAS CONTAMINATED WITH RADIOACTIVE TOXIC ELEMENTS IN IT.

WE WORKED WITH THEM TO MAKE SURE THAT WE WERE HEARING WHAT WAS GOING ON WITH THIS COMMUNITY.

WE PROVIDED THEM WITH TECHNICAL ASSISTANCE AND EVENTUALLY A GRANT THAT SUPPORTED THAT COMMUNITY IN ACTUALLY TESTING THEIR OWN DRINKING WATER FOR LEVELS OF RADIOACTIVITY.

AND SURE ENOUGH, THEIR WATER WAS RADIOACTIVE.

ALI: SO HOW ARE THESE COMMUNITIES REACTING TO THESE OFFICES NOW BEING CLOSED?

AMUDALAT: THESE COMMUNITIES ARE DEVASTATED.

THESE COMMUNITIES ARE GUTTED.

I MEAN, THE ENVIRONMENTAL JUSTICE OFFICE REALLY SERVED AS A LIAISON FOR THE COMMUNITY AND THE GOVERNMENT.

THEY WERE ON THE FRONT LINES IN MANY INSTANCES IN THESE REGIONS, REALLY CONNECTING WITH PEOPLE AND UNDERSTANDING WHAT THEIR LOCAL CHALLENGES WERE, CONSIDERING LIKE HE TALKED ABOUT WATER CONTAMINATION, AIR CONTAMINATION, WANTING TO HAVE ELECTRIC SCHOOL BUSES AND SOLAR PANELS.

SO THEY REALLY UNDERSTOOD WHAT WAS HAPPENING ON THE FRONT LINES, AND THEY WERE THE VOICE FOR THOSE COMMUNITIES AND THE GOVERNMENT.

SO TO HAVE THAT OFFICE BE COMPLETELY GUTTED FOR MANY OF THEM MAKES THEM FEEL LIKE A LOT OF THAT RELATIONSHIP IS NOW BEING CUT.

AND IT'S A TRUE UNRAVELING OF NOT ONLY WHAT THE BIDEN ADMINISTRATION WORKED TO DO, BUT THE 30 YEARS ENVIRONMENTAL JUSTICE WORK THAT HAS BEEN HAPPENING IN COUNTRY.

ALI: I'M GOING TO READ FOR YOU A STATEMENT FROM EPA ADMINISTRATOR LEE ZELDIN.

HE SAYS THAT ENVIRONMENTAL JUSTICE SOUNDS LIKE A GOOD IDEA IN THEORY AND RECEIVES BIPARTISAN SUPPORT, BUT IN REALITY, ENVIRONMENTAL JUSTICE HAS BEEN USED PRIMARILY AS AN EXCUSE TO FUND LEFT-WING ACTIVISTS INSTEAD OF ACTUALLY SPENDING THOSE DOLLARS TO DIRECTLY REMEDIATE ENVIRONMENTAL ISSUES FOR THOSE COMMUNITIES.

WHAT DO YOU MAKE OF THAT?

AMUDALAT: THESE OFFICES WEREN'T JUST HELPING SPECIFIC DEI COMMUNITIES OR LEFTIST WOKE COMMUNITIES, BUT THEY WERE HELPING EVERYBODY.

I WENT TO CANCER ALLEY FOR A STORY THAT I WORKED ON.

I WAS AMAZED BUT ALSO SHOCKED BY THE FLARES THAT WOULD GO OFF THAT KIND OF LIT UP THE SKY ALMOST LIKE, IT ALMOST LOOKED LIKE FIREWORKS IN A WEIRD WAY.

AND THE SMELLS THAT I SMELLED, YOU KNOW, I GOT A HEADACHE BEING IN THOSE COMMUNITIES FOR ALMOST AN HOUR OF JUST DRIVING.

AND THAT'S WHAT PEOPLE'S EXPERIENCES WERE EVERY DAY.

IT LEAVES A LOT OF PEOPLE WHO LIVE ON THE FRONT LINES OF THESE COMMUNITIES ABANDONED.

AND IT MEANS THAT FOR THE FUTURE THAT THEY MIGHT BE SICKER, RIGHT?

IT MEANS THAT THEY HAVE A SICKER FUTURE.

IT MEANS THEY DON'T HAVE AS MUCH CLEAN AIR AS THEY WERE STARTING TO DEVELOP.

IT MEANS THEIR WATER COULD BE CONTAMINATED.

AND THERE'S REALLY NOBODY THERE TO HELP THEM.

ALI: AMDALAT AJASA WITH THE WASHINGTON POST, THANK YOU SO MUCH FOR JOINING US.

AMUDALAT: THANK YOU FOR HAVING ME.

JOHN: SINCE THE COLLAPSE OF THE CEASEFIRE BETWEEN ISRAEL AND HAMAS IN EARLY MARCH, GAZA HAS NOT RECEIVED ANY DELIVERIES OF FOOD, WATER, FUEL OR MEDICAL SUPPLIES AS ISRAEL HAS BLOCKED ALL HUMANITARIAN AID.

THAT'S LEFT GAZANS IN DIRE STRAITS.

EARLIER I SPOKE TO GAVIN KELLEHER OF THE NORWEGIAN REFUGEE COUNCIL WHO IS IN GAZA.

>> THE SITUATION HERE ON THE GROUND IN GAZAZ IS ONE OF UTTER DESPERATION.

PEOPLE ARE ALREADY RUNNING OUT OF THINGS THEY NEED TO STAY ALIVE.

CIVILIANS ARE BEING ATTACKED IN INCESSANT MILITARY VIOLENCE, BEING DISPLACED IN THE HUNDREDS OF THOUSANDS, MORE THAN 420,000 PEOPLE DISPLACED IN THE LAST MONTH ALONE.

PEOPLE ARE BEING DENIED ACCESS TO THE BASICS THEY NEED TO SURVIVE, INCLUDING FOOD AND DWINDLING ACCESS TO WATER.

JOHN: GREATEST NEED?

- - IS IT POSSIBLE TO SINGLE OUT ONE GREATEST NEED?

GAVIN: I WOULD SAY ACCESS TO FOOD HAS REACHED A CRITICAL JUNCTURE.

MOST FAMILIES IN GAZA ARE NOW SURVIVING ON ONE MEAL A DAY, MANY SPLITTING THAT MEAL IN HAVE TO GET THROUGH THE DAY.

PEOPLE ARE EXHAUSTING THEIR COPING MECHANISMS NOW TO ACCES FOOD.

PEOPLE ARE SELLING THEIR BELONGINGS, THEY'RE SELLING THEIR CLOTHES, TRYING TO ACCESS CASH TO GET FOOD.

OTHERS ARE BARTERING ON SOCIAL MEDIA.

YOU SEE POSTS OF PEOPLE TRYING TO SELL DIAPERS OR EXCHANGE DIAPERS FOR A BAG OF LENTILS OR COOKING OIL.

BEGGING IS ALSO OVERWHELMING AT THIS POINT, BUT OF COURSE VERY FEW PEOPLE HAVE ANY ABILITY TO ASSIST NOW BECAUSE NOTHING HAS ENTERED GAZA FOR ALMOST 50 DAYS.

JOHN: TALK ABOUT THAT THE , RENEWAL OF FIGHTING THE NEW BLOCKING AID GETTING INTO GAZA 50 DAYS.

HAD THINGS BEEN GETTING BETTER BEFORE THAT?

GAVIN: IN THE PERIOD DURING THE CEASEFIRE, WE WERE ABLE SCALE UP A SHELTER RESPONSE, ACCESS TO FOOD WAS IMPROVED, THE MARKETS WERE INCREASING IN CAPACITY.

WHEN THE CEASE-FIRE COLLAPSED, EVERYTHING CHANGED.

THERE WERE NO SUPPLIES COMING IN BUT NEEDS ARE GROWING AS MORE AND MORE PEOPLE ARE BEING DISPLACED IN THIS VIOLENCE AND WE ARE UNABLE TO SUPPORT THEM.

HUMANITARIAN ORGANIZATIONS ON THE GROUND HAVE HAD OUR HANDS TIED.

JOHN: HOW IS THE SITUATION AFFECTING YOUR GROUP'S ABILITY TO OPERATE?

GAVIN: WE HAVE EMPTY WAREHOUSES, A SMALL NUMBER OF SUPPLIES LEFT IN THE SOUTH WE WILL DISTRIBUTE THE NEXT WEEK.

OTHER THAN THAT, WE'RE CONTRACTING WATER TRUCKS SO PEOPLE CAN STILL HAVE SOME ACCESS TO CLEAN DRINKING WATER.

BUT EVERYTHING HERE IS ON A KNIFE'S EDGE.

AT ANY POINT WE COULD RUN OUT OF ACCESS TO FUEL WHICH IS NEEDED TO CONTINUE PRODUCING WATER IN GAZA AND TO CONTINUE MOVING IT AROUND.

THE HUNGER THAT IS GROWING HERE NOW IS BECOMING THE NUMBER ONE PRIORITY FOR PEOPLE ON THE GROUND.

AS AN ORGANIZATION, WE ARE NOT ABLE TO BRING ANY SUPPLIES IN.

THERE'S NOTHING THAT WE CAN DO AT THIS POINT OTHER THAN CONTINUE TO CALL FOR THE CROSSING POINT INTO GAZA TO BE OPENED.

JOHN: YESTERDAY ISRAELI PRIME MINISTER BENJAMIN NETANYAHU SAID ISRAEL HAD NO CHOICE IN HIS WORDS BUT TO CONTINUE FIGHTING IN GAZA.

HE SAID THE WAR WON'T END BEFORE THEY DESTROY HAMAS, FREE THE HOSTAGES, AND MAKE SURE THAT GAZA IS NO LONGER A THREAT TO ISRAEL.

WHAT DO YOU SAY TO THAT?

GAVIN: I THINK WE HAVE TO SEPARATE OUT THE OBLIGATIONS THAT ISRAEL HAS UNDER INTERNATIONAL HUMANITARIAN LAW.

AT THIS POINT EVERY SINGLE TRUCK OF AID THAT ISRAEL IS DENYING FROM ENTERING GAZA IS RISKING BECOMING A DEATH SENTENCE FOR PEOPLE HERE WHO HAVE ALREADY RUN OUT OF FOOD ON THE GROUND AND IT IS UNACCEPTABLE TO EMPLOY COLLECTIVE PUNISHMENT ON THIS SCALE FOR 2.1 MILLION PEOPLE IN PURSUIT OF MILITARY OBJECTIVES.

JOHN: THE ISRAELIS, OF COURSE SAY THEY ARE FIGHTING HAMAS, NOT GAZANS.

IS IT POSSIBLE TO SEPARATE THE EFFECT BETWEEN THE TWO?

GAVIN: IT IS NOT POSSIBLE TO SEPARATE THE EFFECT BETWEEN THE TWO AT THIS POINT.

WE CONTINUE TO SEE DOZENS OF AIRSTRIKES A DAY WE CONTINUE TO SEE BABIES, , INFANTS, CHILDREN, WOMEN, MEN BEING BLOWN APART WHO ARE VERY CLEARLY CIVILIANS IN THESE WAVES OF MILITARY VIOLENCE.

WE'RE ALSO SEEING THE COLLECTIVE PUNISHMENT WITH THE DENIAL OF ANY AID RESPONSE.

SO RIGHT NOW WE ARE SEEING CIVILIANS IN GAZA SUFFER AND THAT IS UNDENIABLE AT THIS POINT BECAUSE ISRAEL IS PURSUING MILITARY OBJECTIVES WITHOUT ENOUGH CONSIDERATION FOR CIVILIANS ON THE GROUND.

JOHN: YOU SAY THINGS ARE ON A KNIFE'S EDGE.

IS IT POSSIBLE TO SAY THAT IF YOU DON'T GET AID BY A CERTAIN POINT, IT IS THE POINT OF NO RETURN?

GAVIN: WE EXPECT THAT IN THE NEXT WEEK TO TWO WEEKS, THE COMMUNITY KITCHENS WHICH ARE PROVIDING MAYBE ONE MEAL A DAY TO AROUND HALF OF THE FAMILIES IN GAZA WILL FULLY EXHAUST THEIR SUPPLIES BUT I THINK, IF YOU BUILT A WALL AROUND AN AMERICAN CITY OF 2.1 MILLION PEOPLE AND STOPPED LETTING ANYTHING COME IN AT ALL FOR 50 DAYS AND CONTINUED TO PURSUE THAT POLICY, OF COURSE WE ARE GOING TO SEE UNAVOIDABLE DEATHS HERE IN THE TENS OF THOUSANDS IF THE SIEGE IS NOT LIFTED IN THE COMING WEEKS.

JOHN: GAVIN KELLEHER IN GAZA, THANK YOU VERY MUCH.

GAVIN: THANK YOU.

♪ JOHN: FINALLY, THIS PAST WEEK, ASTRONOMERS AT CAMBRIDGE UNIVERSITY MADE HEADLINES WHEN THEY SAID THEY'D SPOTTED INDICATIONS OF POSSIBLE LIFE ON A DISTANT PLANET, USING DATA FROM THE JAMES WEBB SPACE TELESCOPE.

NOW ANOTHER SPACE-BASED OBSERVATORY THAT'S CHANGED WHAT WE KNOW ABOUT THE UNIVERSE IS RETIRING.

THE EUROPEAN SPACE AGENCY'S CRAFT KNOWN AS GAIA IS LEAVING BEHIND A LEGACY OF STUNNING DISCOVERIES.

GAIA BEGAN ITS WORKING LIFE IN 2013 LAUNCHED WITH A CLEAR MISSION, MAP OUR GALAXY AND TELL ITS STORY THE SPACE OBSERVATORY IS EQUIPPED WITH AN ARRAY OF TELESCOPES AND INSTRUMENTS.

FOR MORE THAN A DECADE IS SLOWLY SPUN ABOUT A MILLION MILES FROM EARTH CHARTING THE PRECISE LOCATIONS OF NEARLY 2 BILLION STARS.

>> I DON'T THINK ANYONE CAN IMAGINE LIVING WITHOUT GAIA.

JOHN: ASTRONOMER ANTHONY BROWN FROM THE NETHERLANDS LEADS GAIA 'S DATA PROCESSING AND ANALYSIS.

>> BECAUSE WE HAVE THE POSITIONS, BRIGHTNESS AND COLOR OF 2 BILLION STARS IN THE SKY, WE CAN MAKE A BEAUTIFUL ALL SKY MAP OF THE MILKY WAY.

JOHN: BUT GAIA HAS CREATED MORE THAN BEAUTIFUL MAPS.

ITS DATA LED TO THE REVELATION THAT 10 BILLION YEARS AGO THE YOUNG MILKY WAY COLLIDED AND MERGED WITH A SMALLER GALAXY.

SCIENTISTS ARE STILL EXPLORING THE COSMIC FALLOUT.

>> A LOT OF STARS ARE STILL AROUND AND WE CAN IDENTIFY THEM THINGS TO GAIA.

JOHN: GAIA COMPLETED ONE OF THE MOSTOMPLICATED CELESTIAL CATALOGS IN HISTORY, REVEALING MORE THAN HALF A MILLION NEW STARS IN A CLUSTER KNOWN AS OMEGA CENTAURI.

MANY ZIPPED THROUGH SPACE AT SEVERAL HUNDRED MILES PER HOUR.

SO FAR GAIA'S DATA HAS BEEN USED IN MORE THAN 13,000 STUDIES.

BROWN USED IT TO CHART THE PATH OF STARS IN OUR NIGHT SKY AND PREDICT THEIR MOVEMENTS FOR THE NEXT 1.6 MILLION YEARS.

ITS DETECTION OF A FAINT WOBBLE AND A STAR L L TO AN ASTROPHYSICIST'S DISCOVERY OF A MASSIVE PLANET MANY LIGHT-YEARS AWAY.

>> STARS ARE MASSIVE AND DO NOT MOVE MUCH IN RESPONSE TO THE GRAVITY OF THE PLANET, BUT THE GAIA SPACECRAFT IS PROVIDING JUST THE KIND OF DATA WE NEED.

JOHN: A CORNELL ASTRONOMER USED THESE FINDINGS TO DETERMINE WHAT PLANETS OUTSIDE OUR SOLAR SYSTEM WOULD HAVE A CLEAR VIEW OF EARTH, PART OF THE SEARCH FOR LIFE ELSEWHERE.

>> MORE THAN 1000 STARS COULD SEE US AND WE KNOW WHICH ONES THERE ARE BECAUSE THE GAIA MISSION GIVE US THAT INFORMATION.

ONE OUT OF FIVE STARS HAS A PLANET THAT IS NOT TOO HOT OR TOO COLD TO POTENTIALLY BE LIKE OURS.

JOHN: A DECADE OF HARD WORK NEARLY EXHAUSTED GAIA'S FUEL.

IT WAS TIME TO SAY GOODBYE.

ITS TEAM ON EARTH SENT THE FINAL COMMANDS TO SHUT IT DOWN AND ALSO SEND PHARAOH MESSAGES WHICH WILL FOREVER BE STORED ON THE SPACECRAFT'S ONBOARD MEMORY.

>> WE ARE HUNDREDS OF PEOPLE, THOUSANDS WHO WORKED TOGETHER.

JOHN: THIS PHYSICIST IS THE PROJECT SCIENTIST.

>> WE ARE WITNESSING SOMETHING DEEP THAT IS ENDING.

THERE WERE MANY EMOTIONS, TEARS.

JOHN: GAIA'S WORK MAY BE DONE, BUT IT LEFT PLENTY TO DO ON EARTH.

RESEARCHERS PROCESSED ONLY ABOUT A THIRD OF THE DATA GATHERED.

>> NEXT YEAR WE WILL PUBLISH ANOTHER BIG DATA RELEASED AND THIS WILL OPEN ANOTHER TREASURE TROVE FOR SCIENTISTS TO EXPLORE.

JOHN: LAST MONTH GAIA'S THRUSTERS FIRED ONE LAST TIME TO SEND IT TOWARD THE MOST FAMILIAR STAR, THE MILKY WAY'S PREMIER CARTOGRAPHER WILL SPEND THE REST OF ITS DAYS ORBITING THE SUN, TAKING A PLACE OF ITS OWN IN OUR NIGHT SKY.

♪ JOHN: THAT IS PBS NEWS WEEKEND FOR THIS SUNDAY.

I'M JOHN YANG.

FOR ALL OF MY COLLEAGUES, THANKS FOR JOINING US.

HAPPY EASTER -- HAVE A GOOD WEEK.